Ethical motivations for excluding dairy products are based on issues with the industrial practices behind their production of meat. Concerns include the practice of keeping a cow constantly pregnant in order for her to lactate and the slaughter of unwanted male calves. Other concerns include the standard practice of separating the mother from her calf and denying the calf its natural source of milk. This contrasts with the industrial practices surrounding egg-laying hens, which produce eggs for human consumption without being fertilized. Ovo-vegetarians often prefer free-range eggs, that is, those produced by uncaged hens. Many ovo-vegetarians refuse to eat fertilized eggs, with balut being an extreme example where the egg has developed.
Ethical concerns about the consumption of eggs arise from the practice of culling male chicks shortly after birth. Practices considered humane for chick culling include maceration and suffocation using carbon dioxide.
One of the main differences between a vegan and an ovo-vegetarian diet is the avoidance of eggs. Ethical vegans do not consume eggs because of chick culling. In battery cage egg production, unwanted male chicks are culled or discarded at birth during the process of securing a further generation of egg-laying hens.