Keel bone fractures affect 50-80% of commercial laying hens in some housing systems and represent a massive, largely unaddressed welfare problem in egg production worldwide.
Keel bone fractures represent one of the most widespread but least publicly known welfare problems in animal agriculture. Fractures cause chronic pain in a high proportion of the approximately 7 billion laying hens globally at any given time. The pain suppresses normal behavior — hens with fractures perch and move less, eat less efficiently, and show altered social behavior. The fractures occur across all non-cage housing systems including free-range, suggesting that expanding cage-free housing without addressing fracture risk does not deliver the welfare improvement consumers expect. Addressing keel bone welfare requires breed selection, housing design improvements, and the inclusion of keel bone assessment in welfare monitoring programs.