Osteoporosis and bone fractures are among the most serious welfare problems in laying hens, affecting the majority of birds in commercial flocks by end of life.
Fractures in laying hens cause chronic pain that affects feeding, drinking, and social behaviour. Birds with keel bone fractures show reduced activity, altered posture, and behavioural indicators of pain. The scale of the problem is enormous: billions of hens worldwide experience this condition. While cage-free systems reduce some fracture types, improved genetics, nutrition, and perch design are needed to fully address the welfare problem.