Keel bone fractures affect a majority of laying hens in commercial flocks and cause chronic pain throughout the laying period, representing one of the most prevalent welfare problems in the global egg industry.
Keel bone fractures are perhaps the most overlooked welfare crisis in commercial egg production because they are invisible from the outside and occur across all housing systems — including the free-range and organic systems marketed as higher welfare. The keel bone — the sternum — bears the impact of landing and collision in flocks housed with perches, and its fracture causes chronic pain that persists throughout the laying period. Welfare improvements require multi-pronged approaches: genetic selection for structural resilience, perch design modifications to reduce impact forces, housing layout optimization to prevent collision, and nutritional support for bone quality. No single intervention solves the problem, but the combination can substantially reduce prevalence.