The welfare of laying hens is one of the most studied areas in farm animal science. Battery cage systems deny hens the ability to perform nearly every natural behavior.
Battery cage confinement causes profound welfare deprivation. Hens are behaviorally motivated to perch, dustbathe, forage, and nest — the frustration of these drives in barren cages causes chronic psychological distress measurable through behavioral and physiological indicators. Bone fractures from calcium depletion and lack of exercise affect the majority of battery cage hens. Cage-free systems dramatically improve welfare outcomes for space, behavior, and bone health but require careful management to prevent injurious pecking without beak trimming. Pasture-raised and certified organic systems with outdoor access provide the highest welfare outcomes. The transition from caged to cage-free egg production represents one of the largest current opportunities to reduce farm animal suffering.