Keel bone fractures affect the majority of laying hens in most commercial systems and represent one of the most significant and widespread welfare problems in poultry production.
Keel bone fractures are arguably the most prevalent and underappreciated welfare problem in commercial egg production. Unlike foot pad dermatitis in broilers, which is visible externally, keel fractures are internal and not routinely detected in commercial operations. The birds continue to lay eggs while experiencing chronic pain — fracture sites are frequently associated with callus formation indicating repeated trauma and healing. The transition to cage-free systems was intended as a welfare improvement, and in many respects it was, but falling from elevated perches in poorly designed aviary systems increased keel fracture rates compared to some enriched cage systems. Addressing keel bone welfare requires breed selection for bone strength, perch engineering that reduces impact force on landing, and regular palpation-based monitoring by stockpeople.