Keel bone fractures are an epidemic welfare problem in laying hens, affecting the majority of birds in both conventional and enriched cage-free systems and causing chronic pain throughout the laying period.
Keel bone fractures represent one of the most significant unresolved welfare problems in commercial egg production. The scale of the problem is enormous — the majority of the world's 8 billion laying hens likely sustain keel bone fractures at some point during their productive lives. Fractures cause chronic pain that can be measured through pain behaviour assessment and analgesic treatment trials. The persistence of high fracture rates even in cage-free systems that were designed to improve welfare demonstrates that housing system change alone is insufficient without attention to genetics, perch design, and management. Progress requires a multi-factorial approach including breeding for skeletal robustness, redesigned perching infrastructure, and improved nutrition management.