Laying Hen Keel Bone Fractures: A Hidden Welfare Crisis

Keel bone fractures affect an estimated 50-80% of laying hens in cage-free and free-range systems, causing chronic pain that undermines the welfare gains achieved by moving away from battery cages.

Key Facts

Keel bone fractures affect 50-80% of laying hens in cage-free aviary systems and 30-60% of hens in enriched colony cages, making them the most prevalent welfare problem in modern egg production
The keel bone is the sternum extension to which breast muscles attach, and fractures occur primarily from collision with equipment or hard surfaces during flight in multi-tier aviary systems
Hens with keel bone fractures show pain-associated behaviors including reduced activity, hunched posture, and preference for analgesics when given a choice, confirming these fractures cause chronic pain
Keel bone fractures are difficult to detect visually and typically go undiagnosed and untreated during the laying hen production period
Selective breeding for bone strength, gentler aviary equipment design, and lighting management to reduce collision risk are among the interventions being investigated to reduce fracture prevalence

Welfare Considerations

Keel bone fractures represent a significant welfare problem that undermines the moral case for cage-free egg production as a welfare improvement. While cage-free systems genuinely improve welfare by allowing behavioral expression of nesting, perching, and dust bathing, the high prevalence of painful keel bone fractures in aviary systems means that many hens exchange the immobility of cages for the chronic pain of untreated fractures. This is not an argument for returning to cages, which impose far more severe and comprehensive welfare restrictions, but rather an urgent research and management priority within cage-free systems. The welfare community is increasingly calling for keel bone fracture prevalence to be included as a key performance indicator in egg welfare certification, and for producers to invest in the housing design and genetic improvements that can reduce fracture rates.

What You Can Do

When choosing cage-free eggs, look for certification schemes that include keel bone fracture monitoring as a welfare requirement
Support organizations that include keel bone fracture research and reporting in their egg welfare campaigns and certification criteria
Contact egg certification schemes and major egg producers to ask about their keel bone fracture monitoring programs and targets for reduction
Advocate for mandatory keel bone fracture reporting as a welfare indicator in all national laying hen welfare regulations
Support research into aviary design, breeding, and lighting management interventions that reduce keel bone fracture prevalence in cage-free systems