Intensive animal farming
Intensive animal farming or industrial livestock production, also called factory farming, is a modern form of intensive farming that refers to the industrialized production of livestock, including cattle, poultry (in "Battery cages") and fish in confinement at high stocking density — a practice typical in industrial farming by agribusinesses. The main products of this industry are meat, milk and eggs for human consumption. There are issues regarding whether factory farming is sustainable and ethical.
Confinement at high stocking density is one part of a systematic effort to produce the highest output at the lowest cost by relying on economies of scale, modern machinery, biotechnology, and global trade. Confinement at high stocking density requires the use of antibiotics and pesticides to mitigate the spread of disease and pestilence exacerbated by these crowded living conditions. In addition, antibiotics are used to stimulate livestock growth by killing intestinal bacteria. There are differences in the way factory farming techniques are practiced around the world. There is a continuing debate over the benefits, risks and ethical questions of factory farming. The issues include the efficiency of food production; animal welfare; whether it is essential for feeding the growing global population; and the environmental impact (e.g. pollution) and health risks.
The practice is widespread in developed nations. According to the Worldwatch Institute, as of 2006 74 percent of the world's poultry, 43 percent of beef, 50 percent of pork, and 68 percent of eggs were produced this way.
- 1 History
- 2 Contemporary animal production
- 3 Hogs
- 4 Aquaculture
- 5 Regulation
- 6 Controversies & criticisms
- 7 See also
- 8 References
- 9 Further reading
The practice of industrial animal agriculture is a relatively recent development in the history of agriculture, and the result of scientific discoveries and technological advances. Innovations in agriculture beginning in the late 19th century generally parallel developments in mass production in other industries that characterized the latter part of the Industrial Revolution. The discovery of vitamins and their role in animal nutrition, in the first two decades of the 20th century, led to vitamin supplements, which allowed chickens to be raised indoors. The discovery of antibiotics and vaccines facilitated raising livestock in larger numbers by reducing disease. Chemicals developed for use in World War II gave rise to synthetic pesticides. Developments in shipping networks and technology have made long-distance distribution of agricultural produce feasible.
Agricultural production across the world doubled four times between 1820 and 1975 (1820 to 1920; 1920 to 1950; 1950 to 1965; and 1965 to 1975) to feed a global population of one billion human beings in 1800 and 6.5 billion in 2002.:29 During the same period, the number of people involved in farming dropped as the process became more automated. In the 1930s, 24 percent of the American population worked in agriculture compared to 1.5 percent in 2002; in 1940, each farm worker supplied 11 consumers, whereas in 2002, each worker supplied 90 consumers.:29
According to the BBC, the era factory farming per se in Britain began in 1947 when a new Agriculture Act granted subsidies to farmers to encourage greater output by introducing new technology, in order to reduce Britain's reliance on imported meat. The United Nations writes that "intensification of animal production was seen as a way of providing food security." In 1960s North America, pigs and cows began to be raised on factory farms. From its American and West European heartland factory farming became globalised in the later years of the 20th century and is still expanding and replacing traditional practices of stock rearing in an increasing number of countries. In 1990 factory farming accounted for 30% of world meat production and by 2005 this had risen to 40%.
Contemporary animal production
Factory farms hold large numbers of animals, typically cows, pigs, turkeys, or chickens, often indoors, typically at high densities. The aim of the operation is to produce large quantities of meat, eggs, or milk at the lowest possible cost. Food is supplied in place, and a wide variety of artificial methods are employed to maintain animal health and improve production, such as the use of antimicrobial agents, vitamin supplements, and growth hormones. Physical restraints are used to control movement or actions regarded as undesirable. Breeding programs are used to produce animals more suited to the confined conditions and able to provide a consistent food product.
Factory farming is widespread in developed nations. According to the Worldwatch Institute, as of 2006, 74 percent of the world's poultry, 43 percent of beef, and 68 percent of eggs were produced this way. In the U.S., as of 2000 four companies produced 81 percent of cows, 73 percent of sheep, 60 percent of pigs, and 50 percent of chickens and according to its National Pork Producers Council, 80 million of its 95 million pigs slaughtered each year are reared in industrial settings.:29
In the United States, chickens were raised primarily on family farms until roughly 1960. Originally, the primary value in poultry was eggs, and meat was considered a byproduct of egg production. Its supply was less than the demand, and poultry was expensive. Except in hot weather, eggs can be shipped and stored without refrigeration for some time before going bad; this was important in the days before widespread refrigeration.
Farm flocks tended to be small because the hens largely fed themselves through foraging, with some supplementation of grain, scraps, and waste products from other farm ventures. Such feedstuffs were in limited supply, especially in the winter, and this tended to regulate the size of the farm flocks. Soon after poultry keeping gained the attention of agricultural researchers (around 1896), improvements in nutrition and management made poultry keeping more profitable and businesslike.
Prior to about 1910, chicken was served primarily on special occasions or Sunday dinner. Poultry was shipped live or killed, plucked, and packed on ice (but not eviscerated). The "whole, ready-to-cook broiler" was not popular until the 1950s, when end-to-end refrigeration and sanitary practices gave consumers more confidence. Before this, poultry were often cleaned by the neighborhood butcher, though cleaning poultry at home was a commonplace kitchen skill.
Two kinds of poultry were generally used: broilers or "spring chickens;" young male chickens, a byproduct of the egg industry, which were sold when still young and tender (generally under 3 pounds live weight), and "stewing hens," also a byproduct of the egg industry, which were old hens past their prime for laying.
The major milestone in 20th century poultry production was the discovery of vitamin D, which made it possible to keep chickens in confinement year-round. Before this, chickens did not thrive during the winter (due to lack of sunlight), and egg production, incubation, and meat production in the off-season were all very difficult, making poultry a seasonal and expensive proposition. Year-round production lowered costs, especially for broilers.
At the same time, egg production was increased by scientific breeding. After a few false starts, (such as the Maine Experiment Station's failure at improving egg production) success was shown by Professor Dryden at the Oregon Experiment Station.
Improvements in production and quality were accompanied by lower labor requirements. In the 1930s through the early 1950s, 1,500 hens was considered to be a full-time job for a farm family. In the late 1950s, egg prices had fallen so dramatically that farmers typically tripled the number of hens they kept, putting three hens into what had been a single-bird cage or converting their floor-confinement houses from a single deck of roosts to triple-decker roosts. Not long after this, prices fell still further and large numbers of egg farmers left the business.
Robert Plamondon reports that the last family chicken farm in his part of Oregon, Rex Farms, had 30,000 layers and survived into the 1990s. But the standard laying house of the current operators is around 125,000 hens.
This fall in profitability was accompanied by a general fall in prices to the consumer, allowing poultry and eggs to lose their status as luxury foods.
The vertical integration of the egg and poultry industries was a late development, occurring after all the major technological changes had been in place for years (including the development of modern broiler rearing techniques, the adoption of the Cornish Cross broiler, the use of laying cages, etc.).
By the late 1950s, poultry production had changed dramatically. Large farms and packing plants could grow birds by the tens of thousands. Chickens could be sent to slaughterhouses for butchering and processing into prepackaged commercial products to be frozen or shipped fresh to markets or wholesalers. Meat-type chickens currently grow to market weight in six to seven weeks, whereas only fifty years ago it took three times as long. This is due to genetic selection and nutritional modifications (and not the use of growth hormones, which are illegal for use in poultry in the US and many other countries). Once a meat consumed only occasionally, the common availability and lower cost has made chicken a common meat product within developed nations. Growing concerns over the cholesterol content of red meat in the 1980s and 1990s further resulted in increased consumption of chicken.
Today, eggs are produced on large egg ranches on which environmental parameters are well controlled. Chickens are exposed to artificial light cycles to stimulate egg production year-round. In addition, it is a common practice to induce molting through careful manipulation of light and the amount of food they receive in order to further increase egg size and production.
On average, a chicken lays one egg a day, but not on every day of the year. This varies with the breed and time of year. In 1900, average egg production was 83 eggs per hen per year. In 2000, it was well over 300. In the United States, laying hens are butchered after their second egg laying season. In Europe, they are generally butchered after a single season. The laying period begins when the hen is about 18–20 weeks old (depending on breed and season). Males of the egg-type breeds have little commercial value at any age, and all those not used for breeding (roughly fifty percent of all egg-type chickens) are killed soon after hatching. The old hens also have little commercial value. Thus, the main sources of poultry meat 100 years ago (spring chickens and stewing hens) have both been entirely supplanted by meat-type broiler chickens.
Some believe the "deadly H5N1 strain of bird flu is essentially a problem of industrial poultry practices". Others have a more nuanced position. According to the CDC article H5N1 Outbreaks and Enzootic Influenza by Robert G. Webster et al.:"Transmission of highly pathogenic H5N1 from domestic poultry back to migratory waterfowl in western China has increased the geographic spread. The spread of H5N1 and its likely reintroduction to domestic poultry increase the need for good agricultural vaccines. In fact, the root cause of the continuing H5N1 pandemic threat may be the way the pathogenicity of H5N1 viruses is masked by cocirculating influenza viruses or bad agricultural vaccines." Dr. Robert Webster explains: "If you use a good vaccine you can prevent the transmission within poultry and to humans. But if they have been using vaccines now [in China] for several years, why is there so much bird flu? There is bad vaccine that stops the disease in the bird but the bird goes on pooping out virus and maintaining it and changing it. And I think this is what is going on in China. It has to be. Either there is not enough vaccine being used or there is substandard vaccine being used. Probably both. It’s not just China. We can’t blame China for substandard vaccines. I think there are substandard vaccines for influenza in poultry all over the world." 
In response to the same concerns, Reuters reports Hong Kong infectious disease expert Lo Wing-lok saying, "The issue of vaccines has to take top priority," and Julie Hall, in charge of the WHO's outbreak response in China, saying China's vaccinations might be masking the virus."  The BBC reported that Dr Wendy Barclay, a virologist at the University of Reading, UK said: "The Chinese have made a vaccine based on reverse genetics made with H5N1 antigens, and they have been using it. There has been a lot of criticism of what they have done, because they have protected their chickens against death from this virus but the chickens still get infected; and then you get drift – the virus mutates in response to the antibodies – and now we have a situation where we have five or six 'flavours' of H5N1 out there."  Keeping wild birds away from domestic birds is known to be key in the fight against H5N1. Caging (no free range poultry) is one way. Providing wild birds with restored wetlands so they naturally choose nonlivestock areas is another way that helps accomplish this. Political forces are increasingly demanding the selection of one, the other, or both based on nonscientific reasons.
Cattle, colloquially referred to as cows, are domesticated ungulates, a member of the family Bovidae, in the subfamily Bovinae, and descended from the aurochs (Bos primigenius). They are raised as livestock for meat (called beef and veal), dairy products (milk), leather and as draught animals (pulling carts, plows and the like). In some countries, such as India, they are honored in religious ceremonies and revered. It is estimated that there are 1.4 billion head of cattle in the world today.
Cattle are often raised by allowing herds to graze on the grasses of large tracts of rangeland called ranches. Raising cattle in this manner allows the productive use of land that might be unsuitable for growing crops. The most common interactions with cattle involve daily feeding, cleaning and milking. Many routine husbandry practices involve ear tagging, dehorning, loading, medical operations, vaccinations and hoof care, as well as training for agricultural shows and preparations. There are also some cultural differences in working with cattle - the cattle husbandry of Fulani men rests on behavioural techniques, whereas in Europe cattle are controlled primarily by physical means like fences.
Once cattle obtain an entry-level weight, about 650 pounds (300 kg), they are transferred from the range to a feedlot to be fed a specialized animal feed which consists of corn byproducts (derived from ethanol production), barley, and other grains as well as alfalfa and cottonseed meal. The feed also contains premixes composed of microingredients such as vitamins, minerals, chemical preservatives, antibiotics, fermentation products, and other essential ingredients that are purchased from premix companies, usually in sacked form, for blending into commercial rations. Because of the availability of these products, a farmer using their own grain can formulate their own rations and be assured the animals are getting the recommended levels of minerals and vitamins.
Breeders can utilise cattle husbandry to reduce M. bovis infection susceptibility by selective breeding and maintaining herd health to avoid concurrent disease. Cattle are farmed for beef, veal, dairy, leather and they are sometimes used simply to maintain grassland for wildlife - for example, in Epping Forest, England. They are often used in some of the most wild places for livestock. Depending on the breed, cattle can survive on hill grazing, heaths, marshes, moors and semi desert. Modern cows are more commercial than older breeds and having become more specialised are less versatile. For this reason many smaller farmers still favour old breeds, such as the dairy breed of cattle Jersey.
There are many potential impacts on human health due to the modern cattle industrial agriculture system. There are concerns surrounding the antibiotics and growth hormones used, increased E. Coli contamination, higher saturated fat contents in the meat because of the feed, and also environmental concerns.
As of 2010, in the U.S. 766,350 producers participate in raising beef. The beef industry is segmented with the bulk of the producers participating in raising beef calves. Beef calves are generally raised in small herds, with over 90% of the herds having less than 100 head of cattle. Fewer producers participate in the finishing phase which often occurs in a feedlot, but nonetheless there are 82,170 feedlots in the United States.
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According to Denis Avery of the Hudson Institute, Asia increased its consumption of pork by 18 million tons in the 1990s.:29 As of 1997, the world had a stock of 900 million pigs, which Avery predicts will rise to 2.5 billion pigs by 2050.:30 He told the College of Natural Resources at the University of California, Berkeley that three billion pigs will thereafter be needed annually to meet demand.:30
Aquaculture is the cultivation of the natural produce of water (fish, shellfish, algae and other aquatic organisms). The term is distinguished from fishing by the idea of active human effort in maintaining or increasing the number of organisms involved, as opposed to simply taking them from the wild. Subsets of aquaculture include Mariculture (aquaculture in the ocean); Algaculture (the production of kelp/seaweed and other algae); Fish farming (the raising of catfish, tilapia and milkfish in freshwater and brackish ponds or salmon in marine ponds); and the growing of cultured pearls. Extensive aquaculture is based on local photosynthetical production while intensive aquaculture is based on fish fed with an external food supply.
Aquaculture has been used since ancient times and can be found in many cultures. Aquaculture was used in China c. 2500 BC. When the waters lowered after river floods, some fishes, namely carp, were held in artificial lakes. Their brood were later fed using nymphs and silkworm feces, while the fish themselves were eaten as a source of protein. The Hawaiian people practiced aquaculture by constructing fish ponds (see Hawaiian aquaculture). A remarkable example from ancient Hawaii is the construction of a fish pond, dating from at least 1,000 years ago, at Alekoko. The Japanese practiced cultivation of seaweed by providing bamboo poles and, later, nets and oyster shells to serve as anchoring surfaces for spores. The Romans often bred fish in ponds.
The practice of aquaculture gained prevalence in Europe during the Middle Ages, since fish were scarce and thus expensive. However, improvements in transportation during the 19th century made fish easily available and inexpensive, even in inland areas, causing a decline in the practice. The first North American fish hatchery was constructed on Dildo Island, Newfoundland Canada in 1889, it was the largest and most advanced in the world.
Americans were rarely involved in aquaculture until the late 20th century, but California residents harvested wild kelp and made legal efforts to manage the supply starting c. 1900, later even producing it as a wartime resource. (Peter Neushul, Seaweed for War: California's World War I kelp industry, Technology and Culture 30 (July 1989), 561–583)
In contrast to agriculture, the rise of aquaculture is a contemporary phenomenon. According to professor Carlos M. Duarte About 430 (97%) of the aquatic species presently in culture have been domesticated since the start of the 20th century, and an estimated 106 aquatic species have been domesticated over the past decade. The domestication of an aquatic species typically involves about a decade of scientific research. Current success in the domestication of aquatic species results from the 20th century rise of knowledge on the basic biology of aquatic species and the lessons learned from past success and failure. The stagnation in the world's fisheries and overexploitation of 20 to 30% of marine fish species have provided additional impetus to domesticate marine species, just as overexploitation of land animals provided the impetus for the early domestication of land species.
In the 1960s, the price of fish began to climb, as wild fish capture rates peaked and the human population continued to rise. Today, commercial aquaculture exists on an unprecedented, huge scale. In the 1980s, open-netcage salmon farming also expanded; this particular type of aquaculture technology remains a minor part of the production of farmed finfish worldwide, but possible negative impacts on wild stocks, which have come into question since the late 1990s, have caused it to become a major cause of controversy.
In 2003, the total world production of fisheries product was 132.2 million tonnes of which aquaculture contributed 41.9 million tonnes or about 31% of the total world production. The growth rate of worldwide aquaculture is very rapid (greater than 10% per year for most species) while the contribution to the total from wild fisheries has been essentially flat for the last decade.
In the US, approximately 90% of all shrimp consumed are farmed and imported. In recent years salmon aquaculture has become a major export in southern Chile, especially in Puerto Montt and Quellón, Chile's fastest-growing city.
Farmed fish are kept in concentrations never seen in the wild, e.g. 50,000 fish in a 2-acre (8,100 m2) area, with each fish occupying less room than the average bathtub. This can cause several forms of pollution. Packed tightly, fish rub against each other and the sides of their cages, damaging their fins and tails and becoming sickened with various diseases and infections.
Some species of sea lice have been noted to target farmed coho and farmed Atlantic salmon specifically. Such parasites may have an effect on nearby wild fish. For these reasons, aquaculture operators frequently need to use strong drugs to keep the fish alive (but many fish still die prematurely at rates of up to 30%) and these drugs inevitably enter the environment.
The lice and pathogen problems of the 1990s facilitated the development of current treatment methods for sea lice and pathogens. These developments reduced the stress from parasite/pathogen problems. However, being in an ocean environment, the transfer of disease organisms from the wild fish to the aquaculture fish is an ever-present risk factor.
The very large number of fish kept long-term in a single location produces a significant amount of condensed feces, often contaminated with drugs, which again affect local waterways. However, these effects appear to be local to the actual fish farm site and may be minimal to non-measurable in high current sites.
Integrated Multi-trophic Aquaculture
Integrated Multi-Trophic Aquaculture (IMTA) is a practice in which the by-products (wastes) from one species are recycled to become inputs (fertilizers, food) for another. Fed aquaculture (e.g. fish, shrimp) is combined with inorganic extractive (e.g. seaweed) and organic extractive (e.g. shellfish) aquaculture to create balanced systems for environmental sustainability (biomitigation), economic stability (product diversification and risk reduction) and social acceptability (better management practices).
"Multi-Trophic" refers to the incorporation of species from different trophic or nutritional levels in the same system. This is one potential distinction from the age-old practice of aquatic polyculture, which could simply be the co-culture of different fish species from the same trophic level. In this case, these organisms may all share the same biological and chemical processes, with few synergistic benefits, which could potentially lead to significant shifts in the ecosystem. Some traditional polyculture systems may, in fact, incorporate a greater diversity of species, occupying several niches, as extensive cultures (low intensity, low management) within the same pond. The "Integrated" in IMTA refers to the more intensive cultivation of the different species in proximity of each other, connected by nutrient and energy transfer through water, but not necessarily right at the same location.
Ideally, the biological and chemical processes in an IMTA system should balance. This is achieved through the appropriate selection and proportions of different species providing different ecosystem functions. The co-cultured species should be more than just biofilters; they should also be harvestable crops of commercial value. A working IMTA system should result in greater production for the overall system, based on mutual benefits to the co-cultured species and improved ecosystem health, even if the individual production of some of the species is lower compared to what could be reached in monoculture practices over a short term period.
Sometimes the more general term "Integrated Aquaculture" is used to describe the integration of monocultures through water transfer between organisms. For all intents and purposes however, the terms "IMTA" and "integrated aquaculture" differ primarily in their degree of descriptiveness. These terms are sometimes interchanged. Aquaponics, fractionated aquaculture, IAAS (integrated agriculture-aquaculture systems), IPUAS (integrated peri-urban-aquaculture systems), and IFAS (integrated fisheries-aquaculture systems) may also be considered variations of the IMTA concept.
A shrimp farm is an aquaculture business for the cultivation of marine shrimp or prawns for human consumption. Commercial shrimp farming began in the 1970s, and production grew steeply, particularly to match the market demands of the USA, Japan and Western Europe. The total global production of farmed shrimp reached more than 1.6 million tonnes in 2003, representing a value of nearly 9 Billion US$. About 75% of farmed shrimp is produced in Asia, in particular in China and Thailand. The other 25% is produced mainly in Latin America, where Brazil is the largest producer. The largest exporting nation is Thailand.
Shrimp farming has moved from china to Southeast Asia into a meat packing industry. Technological advances have led to growing shrimp at ever higher densities, and broodstock is shipped worldwide. Virtually all farmed shrimp are penaeids (i.e., of the family Penaeidae), and just two species of shrimp—the Penaeus vannamei (Pacific white shrimp) and the Penaeus monodon (giant tiger prawn)—account for roughly 80% of all farmed shrimp. These industrial monocultures are very susceptible to diseases, which have caused several regional wipe-outs of farm shrimp populations. Increasing ecological problems, repeated disease outbreaks, and pressure and criticism from both NGOs and consumer countries led to changes in the industry in the late 1990s and generally stronger regulation by governments.
Factory farms under United States laws and regulations are called concentrated animal feeding operations (CAFOs), and in Canada they are called confined animal feeding operations (CFOs) or intensive livestock operations (ILOs). The designation of CAFOs in the US resulted from that country's 1972 Federal Clean Water Act, which was enacted to protect and restore lakes and rivers to a "fishable, swimmable" quality. The United States Environmental Protection Agency (EPA) identified certain animal feeding operations, along with many other types of industry, as point source polluters of groundwater. These operations were designated as CAFOs and subject to special anti-pollution regulation.
In the United States, farmed animals are excluded by half of all state animal cruelty laws including the federal Animal Welfare Act. The 28 hour law, enacted in 1873 and amended in 1994 states that when animals are being transported for slaughter, the vehicle must stop every 28 hours and the animals must be let out for exercise, food, and water. The United States Department of Agriculture claims that the law does not apply to birds. The Humane Methods of Livestock Slaughter Act is similarly limited. Originally passed in 1958, the Act requires that livestock be stunned into unconsciousness prior to slaughter. This Act also excludes birds, who make up more than 90 percent of the animals slaughtered for food, as well as rabbits and fish. Individual states all have their own animal cruelty statutes; however many states have a provision to exempt standard agricultural practices.
In the United States there is a growing movement to mitigate the worst abuses by regulating factory farming. In Ohio animal welfare organizations reached a negotiated settlement with farm organizations while in California Proposition 2, Standards for Confining Farm Animals, an initiated law was approved by voters in 2008. Regulations have been enacted in other states and plans are underway for referendum and lobbying campaigns in other states.
An action plan has been proposed by the USDA in February 2009, called the Utilization of Manure and Other Agricultural and Industrial Byproducts. This program’s goal is to protect the environment and human and animal health by using manure in a safe and effective manner. In order for this to happen, several actions need to be taken and these four components include : • Improving the Usability of Manure Nutrients through More Effective Animal Nutrition and Management • Maximizing the Value of Manure through Improved Collection, Storage, and Treatment Options • Utilizing Manure in Integrated Farming Systems to Improve Profitability and Protect Soil, Water, and Air Quality • Using Manure and Other Agricultural Byproducts as a Renewable Energy Source
In 2012 Australia's largest supermarket chain, Coles, announced that as of January 1, 2013, they will stop selling company branded pork and eggs from animals kept in factory farms. The nation's other dominant supermarket chain, Woolworths, has already begun phasing out factory farmed animal products. All of Woolworth's house brand eggs are now cage-free, and by mid-2013 all of their pork will come from farmers who operate stall-free farms.
Controversies & criticisms
Advocates of factory farming claim that factory farming has led to the betterment of housing, nutrition, and disease control over the last twenty years, while opponents claim that it harms the environment, creates health risks, and abuses animals.
Animal welfare impacts of factory farming can include:
- Close confinement systems (cages, crates) or lifetime confinement in indoor sheds
- Discomfort and injuries caused by inappropriate flooring and housing
- Restriction or prevention of normal exercise and most of natural foraging or exploratory behaviour
- Restriction or prevention of natural maternal nesting behaviour
- Lack of daylight or fresh air and poor air quality in animal sheds
- Social stress and injuries caused by overcrowding
- Health problems caused by extreme selective breeding and management for fast growth and high productivity
- Reduced lifetime (longevity) of breeding animals (dairy cows, breeding sows)
- Fast-spreading infections encouraged by crowding and stress in intensive conditions
- Debeaking (beak trimming or shortening) in the poultry and egg industry to avoid pecking in overcrowded quarters
- Forced and over feeding (by inserting tubes into the throats of ducks) in the production of foie gras
Confinement and overcrowding of animals results in a lack of exercise and natural locomotory behavior, which weakens their bones and muscles. An intensive poultry farm provides the optimum conditions for viral mutation and transmission – thousands of birds crowded together in a closed, warm, and dusty environment is highly conducive to the transmission of a contagious disease. Selecting generations of birds for their faster growth rates and higher meat yields has left birds’ immune systems less able to cope with infections and there is a high degree of genetic uniformity in the population, making the spread of disease more likely. Further intensification of the industry has been suggested by some as the solution to avian flu, on the rationale that keeping birds indoors will prevent contamination. However, this relies on perfect, fail-safe biosecurity – and such measures are near impossible to implement. Movement between farms by people, materials, and vehicles poses a threat and breaches in biosecurity are possible. Intensive farming may be creating highly virulent avian flu strains. With the frequent flow of goods within and between countries, the potential for disease spread is high.
Confinement and overcrowding of animals' environment presents the risk of contamination of the meat from viruses and bacteria. Feedlot animals reside in crowded conditions and often spend their time standing in their own waste. A dairy farm with 2,500 cows may produce as much waste as a city of 411,000 people, and unlike a city in which human waste ends up at a sewage treatment plant, livestock waste is not treated. As a result, feedlot animals have the potential of exposure to various viruses and bacteria via the manure and urine in their environment. Furthermore, the animals often have residual manure on their bodies when they go to slaughter. Sometimes, even "free-range" animals are mutilated without the use of painkillers.
Confinement at high stocking density requires antibiotics and pesticides to mitigate the spread of disease and pestilence exacerbated by these crowded living conditions. In addition, antibiotics are used to stimulate livestock growth by killing intestinal bacteria. According to a February 2011 FDA report, nearly 29 million pounds of antimicrobials were sold in 2009 for both therapeutic and non-therapeutic use for all farm animal species. The Union of Concerned Scientists estimates that 70% of that amount is for non-therapeutic use.
The large concentration of animals, animal waste, and the potential for dead animals in a small space poses ethical issues. It is recognized that some techniques used to sustain intensive agriculture can be cruel to animals such as mutilation. As awareness of the problems of intensive techniques has grown, there have been some efforts by governments and industry to remove inappropriate techniques.
On some farms, chicks may be debeaked when very young, causing pain and shock. Confining hens and pigs in crates no larger than the animal itself may lead to physical problems such as osteoporosis and joint pain, and psychological problems including boredom, depression, and frustration, as shown by repetitive or self-destructive actions.
In the UK, the Farm Animal Welfare Council was set up by the government to act as an independent advisor on animal welfare in 1979 and expresses its policy as five freedoms: from hunger & thirst; from discomfort; from pain, injury or disease; to express normal behavior; from fear and distress.
There are differences around the world as to which practices are accepted and there continue to be changes in regulations with animal welfare being a strong driver for increased regulation. For example, the EU is bringing in further regulation to set maximum stocking densities for meat chickens by 2010, where the UK Animal Welfare Minister commented, "The welfare of meat chickens is a major concern to people throughout the European Union. This agreement sends a strong message to the rest of the world that we care about animal welfare.”
Factory farming is greatly debated throughout Australia, with many people disagreeing with the methods and ways in which the animals in factory farms are treated. Animals are often under stress from being kept in confined spaces and will attack each other. In an effort to prevent injury leading to infection, their beaks, tails and teeth are removed. Many piglets will die of shock after having their teeth and tails removed, because painkilling medicines are not used in these operations. Others say that factory farms are a great way to gain space, with animals such as chickens being kept in spaces smaller than an A4 page.
Less cruel methods of factory farming are still preferable. For example, in the UK, de-beaking of chickens is deprecated, but it is recognized that it is a method of last resort, seen as better than allowing vicious fighting and ultimately cannibalism. Between 60 and 70 percent of six million breeding sows in the U.S. are confined during pregnancy, and for most of their adult lives, in 2 ft (0.61 m) by 7 ft (2.1 m) gestation crates. According to pork producers and many veterinarians, sows will fight if housed in pens. The largest pork producer in the U.S. said in January 2007 that it will phase out gestation crates by 2017. They are being phased out in the European Union, with a ban effective in 2013 after the fourth week of pregnancy. With the evolution of factory farming, there has been a growing awareness of the issues amongst the wider public, not least due to the efforts of animal rights and welfare campaigners. As a result gestation crates, one of the more contentious practices, are the subject of laws in the U.S., Europe and around the world to phase out their use as a result of pressure to adopt less confined practices.
Human health impact
According to the U.S. Centers for Disease Control and Prevention (CDC), farms on which animals are intensively reared can cause adverse health reactions in farm workers. Workers may develop acute and chronic lung disease, musculoskeletal injuries, and may catch infections that transmit from animals to human beings (such as tuberculosis).
Pesticides are used to control organisms which are considered harmful and they save farmers money by preventing product losses to pests. In the US, about a quarter of pesticides used are used in houses, yards, parks, golf courses, and swimming pools and about 70% are used in agriculture. However, pesticides can make their way into consumers' bodies which can cause health problems. One source of this is bioaccumulation in animals raised on factory farms.
"Studies have discovered an increase in respiratory, neurobehavioral, and mental illnesses among the residents of communities next to factory farms." 
The CDC writes that chemical, bacterial, and viral compounds from animal waste may travel in the soil and water. Residents near such farms report problems such as unpleasant smell, flies and adverse health effects.
The CDC has identified a number of pollutants associated with the discharge of animal waste into rivers and lakes, and into the air. The use of antibiotics may create antibiotic-resistant pathogens; parasites, bacteria, and viruses may be spread; ammonia, nitrogen, and phosphorus can reduce oxygen in surface waters and contaminate drinking water; pesticides and hormones may cause hormone-related changes in fish; animal feed and feathers may stunt the growth of desirable plants in surface waters and provide nutrients to disease-causing micro-organisms; trace elements such as arsenic and copper, which are harmful to human health, may contaminate surface waters.
Intensive farming may make the evolution and spread of harmful diseases easier. Many communicable animal diseases spread rapidly through densely spaced populations of animals and crowding makes genetic reassortment more likely. However small family farms are more likely to introduce bird diseases and more frequent association with people into the mix, as happened in the 2009 flu pandemic
In the European Union, growth hormones are banned on the basis that there is no way of determining a safe level. The UK has stated that in the event of the EU raising the ban at some future date, to comply with a precautionary approach, it would only consider the introduction of specific hormones, proven on a case by case basis. In 1998, the European Union banned feeding animals antibiotics that were found to be valuable for human health. Furthermore, in 2006 the European Union banned all drugs for livestock that were used for growth promotion purposes. As a result of these bans, the levels of antibiotic resistance in animal products and within the human population showed a decrease.
The various techniques of factory farming have been associated with a number of European incidents where public health has been threatened or large numbers of animals have had to be slaughtered to deal with disease. Where disease breaks out, it may spread more quickly, not only due to the concentrations of animals, but because modern approaches tend to distribute animals more widely. The international trade in animal products increases the risk of global transmission of virulent diseases such as swine fever, BSE, foot and mouth and bird flu.
In the United States, the use of antibiotics in livestock is still prevalent. The FDA reports that 80 percent of all antibiotics sold in 2009 were administered to livestock animals, and that many of these antibiotics are identical or closely related to drugs used for treating illnesses in humans. Consequently, many of these drugs are losing their effectiveness on humans, and the total healthcare costs associated with drug-resistant bacterial infections in the United States are between $16.6 billion and $26 billion annually.
Methicillin-resistant Staphylococcus aureus (MRSA) has been identified in pigs and humans raising concerns about the role of pigs as reservoirs of MRSA for human infection. One study found that 20% of pig farmers in the United States and Canada in 2007 harbored MRSA. A second study revealed that 81% of Dutch pig farms had pigs with MRSA and 39% of animals at slaughter carried the bug were all of the infections were resistant to tetracycline and many were resistant to other antimicrobials. A more recent study found that MRSA ST398 isolates were less susceptible to tiamulin, an antimicrobial used in agriculture, than other MRSA or methicillin susceptible S. aureus. Cases of MRSA have increased in livestock animals. CC398 is a new clone of MRSA that has emerged in animals and is found in intensively reared production animals (primarily pigs, but also cattle and poultry), where it can be transmitted to humans. Although dangerous to humans, CC398 is often asymptomatic in food-producing animals.
A 2011 nationwide study reported nearly half of the meat and poultry sold in U.S. grocery stores — 47 percent — was contaminated with S. aureus, and more than half of those bacteria — 52 percent — were resistant to at least three classes of antibiotics. Although Staph should be killed with proper cooking, it may still pose a risk to consumers through improper food handling and cross-contamination in the kitchen. The senior author of the study said, "The fact that drug-resistant S. aureus was so prevalent, and likely came from the food animals themselves, is troubling, and demands attention to how antibiotics are used in food-animal production today."
In April 2009, lawmakers in the Mexican state of Veracruz accused large-scale hog and poultry operations of being breeding grounds of a pandemic swine flu, although they did not present scientific evidence to support their claim. A swine flu which quickly killed more than 100 infected persons in that area, appears to have begun in the vicinity of a Smithfield subsidiary pig CAFO (concentrated animal feeding operation).
Concentrating large numbers of animals in factory farms is a major contribution to global environmental degradation, through the need to grow feed (often by intensive methods using excessive fertiliser and pesticides), pollution of water, soil and air by agrochemicals and manure waste, and use of limited resources (water, energy).
Livestock production is also particularly water-intensive in indoor, intensive systems. Eight percent of global human water use goes towards animal production, including water used to irrigate feed crops.
Industrial production of pigs and poultry is an important source of GHG emissions and is predicted to become more so. On intensive pig farms, the animals are generally kept on concrete with slats or grates for the manure to drain through. The manure is usually stored in slurry form (slurry is a liquid mixture of urine and feces). During storage on farm, slurry emits methane and when manure is spread on fields it emits nitrous oxide and causes nitrogen pollution of land and water. Poultry manure from factory farms emits high levels of nitrous oxide and ammonia.
Environmental impacts of factory farming can include:
- Deforestation for animal feed production
- Unsustainable pressure on land for production of high-protein/high-energy animal feed
- Pesticide, herbicide and fertilizer manufacture and use for feed production
- Unsustainable use of water for feed-crops, including groundwater extraction
- Pollution of soil, water and air by nitrogen and phosphorus from fertiliser used for feed-crops and from manure
- Land degradation (reduced fertility, soil compaction, increased salinity, desertification)
- Loss of biodiversity due to eutrophication, acidification, pesticides and herbicides
- Worldwide reduction of genetic diversity of livestock and loss of traditional breeds
- Species extinctions due to livestock-related habitat destruction (especially feed-cropping)
Small farmers are often absorbed into factory farm operations, acting as contract growers for the industrial facilities. In the case of poultry contract growers, farmers are required to make costly investments in construction of sheds to house the birds, buy required feed and drugs - often settling for slim profit margins, or even losses. Factory farm workers also cite the repetitive actions and high line speeds that are features of the large-scale slaughtering and processing facilities that characterize the factory farming poultry sectors, as causing injuries and illness to workers. Forced labor is another problem encountered in factory farming system. Greenpeace’s report  described a set of poor labor conditions at Roncador Farm in Mato Grosso, where workers are responsible for maintaining more than 100,000 cattle and 4,000 ha (9,000 ac) of soybeans:
"Working 16 hours a day, seven days a week, the laborers were forced to live in plastic shanties with no beds or sanitary provision. Water for washing, cooking and drinking came from a cattle watering hole and was stored in barrels previously used for diesel oil and lubricants. There was no opportunity to leave the farm. Goods had to be bought from the farm shop at extortionate prices, putting laborers into ever-increasing debt, which they would never be able to pay off—a form of slavery known as debt bondage." Even with laborers knowing this consciously, they have no choice but to abide to what they have due to the fact of their move from home, and fear of losing everything they currently have.
While federal and state labor laws are intended to protect all workers equally, many violations of these laws occur in the factory farms of the United States. Many factory farm workers are undocumented immigrants that farming businesses find ideal to hire because they are less likely to complain about low wages and hazardous working conditions. Using undocumented workers allows companies to easily replace them when a worker dies or gets injured. These illegal workers can also be easily persuaded to drop unfair labor charges when companies threaten to go to authorities regarding illegal immigration status.
The major concentration of the industry occurs at the slaughter and meat processing phase, with only four companies slaughtering and processing 81 percent of cows, 73 percent of sheep, 57 percent of pigs and 50 percent of chickens. This concentration at the slaughter phase may be in large part due to regulatory barriers that may make it financially difficult for small slaughter plants to be built, maintained or remain in business. Factory farming may be no more beneficial to livestock producers than traditional farming because it appears to contribute to overproduction that drives down prices. Through “forward contracts” and “marketing agreements,” meatpackers are able to set the price of livestock long before they are ready for production. These strategies often cause farmers to lose money, as half of all U.S. family farming operations did in 2007.
In 1967, there were one million pig farms in America; as of 2002, there were 114,000.:29
Many of the nation's livestock producers would like to market livestock directly to consumers but with limited USDA inspected slaughter facilities, livestock grown locally can not typically be slaughtered and processed locally.
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- Animal welfare
- Battery cage
- Bernard Matthews
- Cattle Health Initiative
- ConAgra Foods
- Concentrated Animal Feeding Operations
- Controlled-atmosphere killing
- Environmental vegetarianism
- Extensive farming
- Intensive farming
- Intensive pig farming
- Farm Sanctuary
- Farmageddon (book)
- Food systems
- Gestation crate
- Humane Slaughter Act
- Intensive pig farming
- List of foodborne illness outbreaks
- List of United States foodborne illness outbreaks
- Maple Leaf Foods
- Meat Atlas
- Organic farming
- Small-scale agriculture
- Smithfield Foods
- Sustainable agriculture
- System of Rice Intensification
- Tyson Foods
- Sources discussing "intensive farming", "intensive agriculture" or "factory farming":
- Fraser, David. Animal welfare and the intensification of animal production: An alternative interpretation, Food and Agriculture Organization of the United Nations, 2005. *Turner, Jacky. "History of factory farming", United Nations: "Fifty years ago in Europe, intensification of animal production was seen as the road to national food security and a better diet ... The intensive systems – called 'factory farms' – were characterised by confinement of the animals at high stocking density, often in barren and unnatural conditions."
- Simpson, John. Why the organic revolution had to happen, The Observer, April 21, 2001: "Nor is a return to 'primitive' farming practices the only alternative to factory farming and highly intensive agriculture."
- "Head to head: Intensive farming", BBC News, March 6, 2001: "Here, Green MEP Caroline Lucas takes issue with the intensive farming methods of recent decades ... In the wake of the spread of BSE from the UK to the continent of Europe, the German Government has appointed an Agriculture Minister from the Green Party. She intends to end factory farming in her country. This must be the way forward and we should end industrial agriculture in this country as well."
- Sources discussing "industrial farming" , "industrial agriculture" and "factory farming":
- "Annex 2. Permitted substances for the production of organic foods", Food and Agriculture Organization of the United Nations: "'Factory' farming refers to industrial management systems that are heavily reliant on veterinary and feed inputs not permitted in organic agriculture.
- "Head to head: Intensive farming", BBC News, March 6, 2001: "Here, Green MEP Caroline Lucas takes issue with the intensive farming methods of recent decades ... In the wake of the spread of BSE from the UK to the continent of Africa, the German Government has appointed an Agriculture Minister from the Green Party. She intends to end factory farming in her country. This must be the way forward and we should end industrial agriculture in this country as well."
- Kaufmann, Mark. "Largest Pork Processor to Phase Out Crates", The Washington Post, January 26, 2007.
- "EU tackles BSE crisis", BBC News, November 29, 2000.
- "Is factory farming really cheaper?" in New Scientist, Institution of Electrical Engineers, New Science Publications, University of Michigan, 1971, p. 12.
- Danielle Nierenberg (2005) Happier Meals: Rethinking the Global Meat Industry. Worldwatch Paper 121: 5
- Duram, Leslie A. (2010). Encyclopedia of Organic, Sustainable, and Local Food. ABC-CLIO. p. 139. ISBN 0-313-35963-6.
- "Factory farming," Encyclopædia Britannica, 2007.
-  Doug Gurian-Sherman. April 2008. CAFOs Uncovered: The Untold Costs of Confined Animal Feeding Operations, Union of Concerned Scientists, Cambridge, MA.
- The Welfare of Intensively Kept Pigs
- Commissioner points to factory farming as source of contamination
- Rebuilding Agriculture – EPA of UK
- "State of the World 2006," Worldwatch Institute, p. 26.
- State of the World 2006: China and India Hold World in Balance (highlights) http://www.worldwatch.org/state-world-2006-china-and-india-hold-world-balance
- John Steele Gordon (1996) "The Chicken Story", American Heritage, September 1996: 52–67
- Matthew Scully Dominion: The Power of Man, the Suffering of Animals, and the Call to Mercy Macmillan, 2002
- "The History of Factory Farming", United Nations.
- Danielle Nierenburg (2005) Happier Meals: Rethinking the Global Meat Industry. Worldwatch Paper 171: 5
- Meat Atlas 2014 – Facts and figures about the animals we eat , page 20, download Meat Atlas as pdf
- OECD, Agricultural Policy Monitoring and Evaluation 2013, 2013, p. 317, table: "OECD: Producer Single Commodity Transfers (USD)"
- "The Dollar Hen", Milo Hastings, (1909)
- Dryden, James. Poultry Breeding and Management. Orange Judd Press, 1916.
- Plamondon.com: the home of Robert Plamondon and all his works!
- Havenstein, G.B., P.R. Ferket, and M.A. Qureshi, 2003a. Growth, livability, and feed conversion of 1957 versus 2001 broilers when fed representative 1957 and 2001 broiler diets. Poult. Sci. 82:1500–1508
- Grain international, non-profit foundation BBC news CNN
- CDC H5N1 Outbreaks and Enzootic Influenza by Robert G. Webster et al.
- MSNBC quoting Reuters quoting Robert G. Webster
- BBC Bird flu vaccine no silver bullet February 22, 2006
- Breitbart News article Key West Chickens Raise Bird Flu Fears published April 13, 2006. Todau on line article Restoring wetlands key to curbing bird flu: UN published April 13, 2006.
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- Breeds of Cattle at CATTLE TODAY
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- R. A. Zinn, University of California, Davis, A Guide to Feed Mixing
- Krebs JR, Anderson T, Clutton-Brock WT, et al. (1997). Bovine tuberculosis in cattle and badgers: an independent scientific review (PDF). Ministry of Agriculture, Fisheries and Food. Retrieved September 4, 2006.
- Pollan, Michael. 2002. This Steer's Life. The New York Times. March 31.
- National Agricultural Statistics Service (NASS), Agricultural Statistics Board, United States Department of Agriculture (USDA). 2010; Overview of the United States Cattle Industry
- Footnote: According to legend, it was constructed by the mythical Menehune.
- "Fuss Over Farming Fish", Alaska Science Forum, June 27, 1990
- This also causes stress."Facts about Fish and Fish Farming", Advocates for Animals.
- University of Maine, Department of Animal, Veterinary and Aquaculture Sciences, "Sea Lice Information"
- [Lymbery, P. CIWF Trust report, "In Too Deep – The Welfare of Intensively Farmed Fish" (2002)]
- [BULLETIN OF THE EUROPEAN ASSOCIATION OF FISH PATHOLOGISTS 22 (2): 117–125 2002]
- Chopin T, Buschmann AH, Halling C, Troell M, Kautsky N, Neori A, Kraemer GP, Zertuche-Gonzalez JA, Yarish C and Neefus C. 2001. Integrating seaweeds into marine aquaculture systems: a key toward sustainability. Journal of Phycology 37: 975–986.
- Chopin T. 2006. Integrated multi-trophic aquaculture. What it is, and why you should care… and don’t confuse it with polyculture. Northern Aquaculture, Vol. 12, No. 4, July/August 2006, pg. 4.
- Neori A, Chopin T, Troell M, Buschmann AH, Kraemer GP, Halling C, Shpigel M and Yarish C. 2004. Integrated aquaculture: rationale, evolution and state of the art emphasizing seaweed biofiltration in modern mariculture. Aquaculture 231: 361–391.
- "Concentrated animal feeding operations", Centers for Disease Control and Prevention, United States Department of Health and Human Services.
- "Managing the Transition Between Municipal and Provincial Governance as Required by the Regulations Under the Nutrient Management Act" Section:"Lessons From Michigan: Strategies For Regulating Intensive Livestock Operations- Right To Farm And The Role Of The State", Ministry of Agriculture, Food, and Rural Affairs; Government of Ontario, Canada
- Sweeten, John et al. "Fact Sheet #1: A Brief History and Background of the EPA CAFO Rule". MidWest Plan Service, Iowa State University, July 2003.
-  ALDF Farmed Animals and the Law
- Proposition 2, Standards for Confining Farm Animals. Retrieved August 12, 2010.
- "Farmers Lean to Truce on Animals’ Close Quarters" article by Erik Eckholm in The New York Times August 11, 2010. Retrieved August 12, 2010.
- Robbins, Ocean (November 26, 2012). "Is Animal Cruelty Doomed?". Huffington Post.
- McCarthy, Richard; Richard Bennett (1986). "Statutory Protection for Farm Animals". Pace Environmental Law Review 3 (2): 229–256. Retrieved 11 November 2011.
- "Commissioner points to factory farming as source of contamination", CBC, July 28, 2000.
- Blaine Harden (December 28, 2003). "Supplements used in factory farming can spread disease". The Washington Post.
- A. Dennis McBride, MD, MPH (December 7, 1998). "The Association of Health Effects with Exposure to Odors from Hog Farm Operations". North Carolina Department of Health and Human Services.
- Compassion in World Farming – Environment & sustainability
- Force-Fed Animals : The Humane Society of the United States
- Compassion in World Farming – Animal health and disease
- Food Article, Foodborne Illness Information, Pathogen Facts - National Geographic
- "Food Safety Consequences of Factory Farms". Food & Water Watch. March 2007.[dead link]
- New FDA Data Confirm What UCS Has Been Saying For Years: Antimicrobial Use In U.S. Livestock And Poultry Is Massive | Union of Concerned Scientists
- http://www.kt.iger.bbsrc.ac.uk/FACT%20sheet%20PDF%20files/kt32.pdf UK DEFRA comment on de-beaking recognizing it as cruel[dead link]
- "The Welfare of Intensively Kept Pigs—Report of the Scientific Veterinary Committee—Adopted 30 September 1997, European Commission, and "Opinion of the AHAW Panel related to the welfare aspects of various systems of keeping laying hens", European Food Safety Authority (7 March 2005)
- Farm Animal Welfare Council
- DEFRA press release[dead link]
- "Beak trimming". Retrieved 2012-08-05.
- Poulter, Sean (2011-12-16). "Pain of the pigs: Undercover filming shows animals having their teeth clipped off with metal pliers without anaesthetic". Daily Mail (London). Retrieved 2012-08-05.
- Barnett JL, Hemsworth PH, Cronin GM, Jongman EC, and Hutson GD. 2001. "A review of the welfare issues for sows and piglets in relation to housing," Australian Journal of Agricultural Research 52:1–28. Cited in: Pajor EA. 2002. "Group housing of sows in small pens: advantages, disadvantages and recent research," In: Reynells R (ed.), Proceedings: Symposium on Swine Housing and Well-being (Des Moines, Iowa: U.S. Department of Agriculture Agricultural Research Service, June 5, pp. 37–44). In: An HSUS Report: Welfare Issues with Gestation Crates for Pregnant Sows[dead link], Humane Society of the United States.
- The Welfare of Sows in Gestation Crates: A Summary of the Scientific Evidence.[dead link], Farm Sanctuary.
- "An HSUS Report: Welfare Issues with Gestation Crates for Pregnant Sows"[dead link], The Humane Society of the United States, January 6, 2006.
- Hickman, Martin (January 4, 2008). "The true cost of cheap chicken". The Independent (London). Retrieved May 2, 2010.
- Animal rights concerns grow in California
- Washington Post: Largest Pork Processor to Phase Out Crates
- "Factory Farming: The Impact of Animal Feeding Operations on the Environment and Health of Local Communities". Retrieved 2009-12-13.
- The benefits of pesticides: A story worth telling. Purdue.edu. Retrieved on September 15, 2007.
- Kellogg RL, Nehring R, Grube A, Goss DW, and Plotkin S (February 2000), Environmental indicators of pesticide leaching and run-off from farm fields[dead link]. United States Department of Agriculture Natural Resources Conservation Service. Retrieved on 3 October 2007.
- Miller GT (2004), Sustaining the Earth, 6th edition. Thompson Learning, Inc. Pacific Grove, California. Chapter 9, Pages 211–216.
- Sustainable Table article Pesticides
- Pesticides In the Environment[dead link]. Pesticide fact sheets and tutorial, module 6. cornell.edu. Retrieved on September 19, 2007.
- Brown, David (October 25, 2009). "Back where virus started, new scrutiny of pig farming". The Washington Post.
- Food Standards Agency – VPC report on growth hormones in meat
- Schneider K, Garrett L (June 19, 2009). "Non-therapeutic Use of Antibiotics in Animal Agriculture, Corresponding Resistance Rates, and What Can be Done About It".
- "Denmark's Case for Antibiotic-Free Animals". CBS News. February 10, 2010.
- The Hidden Link Between Factory Farms, Toxic Chemicals and Human Illness
- EU‑AGRINET article Fighting swine fever in Europe (Project Coordinator: Dr Trevor Drew at Veterinary Laboratories Agency)
- "H.R. 965: Preservation of Antibiotics for Medical Treatment Act of 2011". 2011-03-09. Retrieved 2012-08-05.
- T. Khannaa, R. Friendshipa, C. Deweya and J.S. Weeseb. Methicillin resistant Staphylococcus aureus colonization in pigs and pig farmers (PDF). Retrieved 2010-11-14.
- de Neeling AJ, van den Broek MJ, Spalburg EC, van Santen-Verheuvel MG, Dam-Deisz WD, Boshuizen HC, van de Giessen AW, van Duijkeren E, Huijsdens XW. High prevalance methicillin resistant Staphylococcus aureus in pigs (PDF). Retrieved 2010-11-14.[dead link]
- Rubin, JE; Ball KR, Chirino-Trejo M (In Press). "Decreased susceptibility of MRSA ST398 to tiamulin". Veterinary Microbiology 151 (3–4): 422–3. doi:10.1016/j.vetmic.2011.03.030. PMID 21511410.
- "Joint scientific report of ECDC, EFSA and EMEA on methicillin resistant Staphylococcus aureus (MRSA) in livestock, companion animals and food". 2009-06-16. Retrieved 2009-09-19.
- "Nationwide study finds U.S. meat and poultry is widely contaminated". 2011-04-15. Retrieved 2012-07-15.
- US meat and poultry is widely contaminated with drug-resistant Staph bacteria, study finds
- David Kirby (2009-04-28). "Mexican Lawmaker: Factory Farms Are "Breeding Grounds" of Swine Flu Pandemic". The Huffington Post. Retrieved 2009-04-28.
- [dead link] America's Animal Factories:How States Fail to Prevent Pollution from Livestock Waste
- "Facts about Pollution from Livestock Farms". National Resource Defense Council. Retrieved 2006-05-30.
- Pollution from Giant Livestock Farms Threatens Public Health
- Contract Farming in the World's Poultry Industry. Grain, Seedling, January 2008
- Eating Up the Amazon
- Greenpeace (2006) Eating up the Amazon, 32.
- FoodIsPower.org - The Food Empowerment Project
- "This Cattleman's Got a Beef". Colorado Springs Independent. November 20, 2003. Retrieved 2012-06-18.
- "Factory Farm Nation: How America Turned its Livestock Farms into Factories". November 2010. Retrieved 2012-07-22.
- Testimony by Leland Swenson, president of the U.S. National Farmers' Union, before the House Judiciary Committee, September 12, 2000.
- CBC News, Berlin protests focus on farming and food safety, Jan 21, 2013
- Deutsche Welle, Protesters in Berlin call for an end to factory farming, 22 January 2011
- Deutsche Welle, Farmers defend themselves at Berlin's Green Week, 17. January 2014
- Government regulation
- National Agriculture Law Center - Animal Feeding Operations
- Brief History of CAFO Regulations – from the National Association of State Departments of Agriculture
- Commissions assessing industrial agriculture
- National Commission on Industrial Farm Animal Production, Independent commission studying the effects of intensive animal production
- Brooman, Simon & Legge, Debbi. Law Relating To Animals. Cavendish Publishing. ISBN 1-84314-129-9
- The State of Meat Production in Developing Countries: 2002[dead link] from The State of the Animals II: 2003[dead link] ISBN 0-9658942-7-4
- Proponent, neutral, and industry-related
- Journal of Extension, article on case studies of the impact of large scale agriculture
- US Farm Bureau, Farm and Ranchers association
- Coalition to Support Iowa Farmers
- Dairy Today magazine
- USDA food safety
- Purdue University food science extension
- Criticism of factory farming
- Baur, Gene (2008). Farm Sanctuary: Changing Hearts and Minds About Animals and Food. Touchstone. ISBN 0-7432-9158-1.
- Bernstein, Mark H. Without a Tear: Our Tragic Relationship With Animals. University of Illinois Press, 2004. ISBN 0-252-07198-0
- Roberts, Paul (2008). The End of Food. Boston: Houghton Mifflin. ISBN 978-0-618-60623-8.
- Foer, Jonathan Safran. "Eating Animals". Little, Brown and Company, 2009. ISBN 0-316-06990-6
- Compassion in World Farming – Publications (various)
- Health Risks of Hog Confinements
- Anti-agricultural FAQs on Factory Farming
- Fatal Harvest – The Tragedy of Industrial Agriculture
- Ask For Change resources for consumers
- A critique of factory farming
- Cruelty to Animals: Mechanized Madness – Article with links to photos and videos of factory farming
- foie gras production – Video of Foie Gras production
- Husbandry Institute Promoting sustainable, responsible, and ethical animal husbandry
- Information about factory farming from The Humane Society of the United States
- Inside the California Egg Industry: An Undercover Investigation – Video of hens in battery cages at various intensive egg farming facilities. (2/4/06)
- The Meatrix – a parody of The Matrix
- The Meatrix 2: Revolting – the second installment of the Meatrix parodying The Matrix
- Meet Your Meat – a PETA-produced factory farm tour narrated by Alec Baldwin
- Factory Farms Blamed for Spread of Bird Flu
- See inside an egg factory farm
- See inside a chicken factory farm
- One of PA's largest egg farms charged with animal cruelty
- TorturedbyTyson.com – Undercover investigation of a Tyson Foods processing plant
- A Consumer Guide for Boycotting Factory Farms: Part One. Organic Consumers Association
- In the Belly of the Beast: Animal Cruelty is the Price We Pay for Cheap Meat. Rolling Stone. December 10, 2013.
- 6 Crimes Against Nature Perpetrated By the Food Industry, AlterNet, 2013.12.19