Keel bone fractures affect the majority of laying hens across all housing systems and represent a major unresolved welfare challenge for the egg industry globally.
Keel bone fractures are paradoxically associated with higher-welfare systems: free-range hens that fly and collide with perches have higher fracture rates than caged hens that never perch. This creates a difficult welfare dilemma — removing cages (good for behaviour) while not adequately preventing fractures (bad for pain). The solution requires integrated interventions: better genetics, perch materials, lighting regimes that prevent panic flying, and monitoring systems that detect affected individuals.