Laying Hen Keel Bone Fractures: Prevalence and Welfare

Keel bone fractures affect the majority of laying hens in commercial flocks globally, causing chronic pain that compromises welfare for much of the production period in one of the most numerous farmed animals.

Key Facts

The keel bone — the breastbone — is fractured in an estimated 50-80% of commercial laying hens in enriched colony systems
Prevalence is highest in aviary systems, where hens collide with perches and structures during flight and landing
Fractures often go undetected because hens mask pain behavioural signs, and routine inspection is infrequent
X-ray and post-mortem studies reveal fractures in hens showing no obvious lameness or behavioural changes
Keel bone fractures cause measurable chronic pain — affected hens show altered movement, reduced activity, and pain responses to palpation
Genetic selection for high egg production has created birds with reduced bone mineralisation and greater fracture susceptibility
Cage-free and free-range systems, despite better welfare in many respects, have higher keel bone fracture rates than cages
Improved perch design, ramp angles, and landing zone padding can reduce impact-related fractures significantly
Selective breeding for stronger bones is technically feasible and has become a welfare priority for leading genetics companies
The welfare cost of keel bone fractures across the global laying flock represents one of the largest known sources of farm animal suffering

Welfare Considerations

Keel bone fractures represent a hidden welfare crisis in egg production — the shift to cage-free systems improved many aspects of hen welfare but inadvertently increased this specific form of chronic pain. Hens with fractured keels live with ongoing discomfort throughout their laying lives, yet the fractures are rarely detected in live birds. Addressing this requires solutions at the breeding level, the housing design level, and the monitoring level — none of which are currently standard requirements in most welfare certification schemes.

What You Can Do

Choose eggs certified under the highest available welfare standards and push for keel bone fracture monitoring requirements
Reduce egg consumption where possible, or choose products from breeds selected for bone strength
Support research into keel bone fracture prevention through genetic selection and housing design improvement
Ask egg producers and retailers what steps they take to monitor and reduce keel bone fracture prevalence
Advocate for keel bone health metrics to be incorporated into welfare certification audits
Support farmed animal welfare organisations working on poultry bone health research and standards