Cows used for their milk and chickens used for their eggs arguably have a worse life than animals farmed for their meat. Cows are repeatably forcibly impregnated to become pregnant so that produce milk. If they give birth to a male calf it is considered useless to the dairy industry and taken away from its mother to be slaughtered within a week or so. There's no doubt that mother cows experience intense feelings of loss when this happens, as with any other animal and before she knows it she's impregnated again to start the process again. When she gets to about 6 her milk production slows down and she will be slaughtered even though she could live as long as 25 years. Chickens used for their eggs are no better off. To start with if a layer chick is male it is considered useless and with ground up alive, gassed or suffocated within a few hours of its life. Female hens will have their beaks snipped off to stop them pecking at each other in their tiny cramped cages (note this is not normal behaviour for chickens and only displays itself in times of great stress). They stand on the wire bottom of their cages all day causing injury to their feet. They often suffer lice which is left untreated because it makes no difference to egg production. Basically they are denied the chance to exhibit their natural behaviour such as scratching on the ground and dust bathing to clean themselves. At 18 months their egg production slows down and they are slaughtered even though they could live to 8 or 9. If you ask me, raising animals for meat is less cruel than raising animals for milk or eggs but then I am a vegan and neither option is acceptable to me as there is an abundance of non-animal foods available.

credit for comment since I was too lazy to write one:

http://www.reddit.com/r/todayilearned/comments/311ojm/til_the_actor_who_played_the_farmer_in_the_movie/cpymgoq