Keel Bone Fractures in Laying Hens

Keel bone fractures affect the majority of laying hens in many commercial systems, causing chronic pain that is now recognised as one of the most significant welfare problems in the egg industry worldwide.

Key Facts

Prevalence exceeds 50-80% in cage-free and aviary systems in many studies
The keel bone runs along the sternum and serves as the anchor for flight muscles
Fractures typically occur from collisions with perches, ramps, and enclosure fittings
Hens with keel fractures show altered posture, gait, and reduced activity
Fractures are largely undetected during routine farm inspections
Selective breeding for high egg production may reduce bone mineralisation
Some breeds show significantly lower fracture rates, indicating genetic solutions exist

Welfare Considerations

Keel bone fractures represent chronic pain lasting weeks to months, with hens often showing reduced access to food and water due to locomotor impairment. The transition from battery cages to cage-free systems, while improving other welfare dimensions, has increased keel fracture rates due to perch collisions and greater activity levels. Research is focused on perch design, breed selection, lighting management, and pullet rearing conditions to reduce injury rates. This welfare problem illustrates how system changes require careful welfare monitoring across all dimensions, not just space allowance.

What You Can Do

Choose eggs from farms using breeds selected for lower keel fracture rates
Support research into perch design standards that reduce collision injuries
Advocate for keel fracture prevalence to be included in farm welfare audits
Reduce egg consumption or shift to plant-based alternatives to lower demand pressure