Battery cages for egg-laying hens have been banned in the EU and several US states, with cage-free systems offering significant welfare improvements though still falling short of high welfare standards.
Battery cage hens live their entire laying lives without being able to spread their wings, dust bathe, perch, or perform any natural chicken behavior. The physical and psychological deprivation is profound for animals with complex behavioral repertoires. Bone density loss from lack of exercise causes painful fractures. Even cage-free systems can have welfare problems from high stocking densities causing aggression. Genuine welfare improvement requires not just cage elimination but provision of real behavioral opportunities - perches, nest boxes, foraging substrate, and ideally outdoor access.