Keel bone fractures affect the majority of laying hens in commercial production, causing chronic pain that is now recognized as one of the most significant welfare issues in poultry farming.
Keel bone fractures represent a major and largely unresolved welfare crisis. The keel bone (sternum) bears significant stress from flight and landing; fractures occur when bones collide with hard surfaces in multi-tier housing. Evidence shows hens with fractures experience chronic pain lasting weeks to months: they show increased sensitivity to touch at the fracture site, altered feeding patterns, and modified behavior consistent with pain. The tragic paradox is that enriched colony and aviary systems — introduced as welfare improvements over battery cages — increased fracture prevalence due to the addition of perches and elevated tiers. Selective breeding for bone robustness and better perch design are promising but slowly implemented solutions.