Battery farmed chicken. Finger lickin good!

Battery hens are caged up in what are essentially factories for the sole purpose of producing eggs. As far as I know, they are fed hormones so that they will keep laying eggs, and never get to see sunlight. Once the chickens are too old/sick to be of any more use, they are culled, ground up, and fed to the remaining hens.

It is also common for pigs to be battery farmed.

While I haven't been inside a battery farm, the chicken truck used to pass by my old house frequently, and I can tell you that the chickens are pretty much shoved into a quick chick brick stack.