Keel Bone Fractures in Laying Hens and Welfare Impact

Keel bone fractures affect the majority of laying hens in cage-free and aviary systems, causing chronic pain that significantly impairs welfare throughout the production period.

Key Facts

Keel bone fractures affect 50-80% of hens in many aviary and free-range systems
The keel bone is a prominent sternum ridge to which flight muscles attach, prone to impact injury
Fractures cause pain evidenced by altered posture, reduced movement, and analgesic-seeking behavior
Hens with fractured keels show reduced feeding, altered social behavior, and abnormal gait
Fractures occur during jumping and landing from elevated perches and during aggressive encounters
Breed selection for lower fracture susceptibility shows promise, with some breeds showing 50% lower rates
Perch height, placement, and material influence fracture risk and can be modified within existing systems

Welfare Considerations

Keel bone fractures represent the most prevalent documented welfare problem in modern cage-free egg production — a system that was introduced to improve hen welfare. The prevalence of 50-80% means that most hens spend a significant portion of their lives with painful skeletal injuries. Behavioral evidence confirms these are not minor injuries: hens with fractured keels preferentially seek analgesic-containing water, directly demonstrating pain motivation. The fact that breed selection and perch design can substantially reduce fracture prevalence means this is a solvable problem, but it requires industry commitment to prioritize welfare outcomes over production efficiency.

What You Can Do

Support egg certification schemes that require keel bone fracture monitoring and reduction targets
Choose eggs from producers using breeds with lower fracture susceptibility where available
Advocate for perch design standards based on evidence of fracture reduction
Support research into housing design innovations that maintain welfare in aviary systems
Engage with retailers about requiring keel bone fracture prevalence disclosure from egg suppliers