Laying Hen Keel Bone Fractures | Animal Welfare Hub

Keel bone fractures are the most prevalent welfare problem in cage-free laying hens, affecting the majority of birds and causing chronic pain.

Key Facts

Keel bone fractures affect 50-80% of laying hens in cage-free aviary systems in some studies
Fractures occur primarily from landing badly from high perches and from collisions within the aviary structure
Keel bone fractures cause chronic pain measurable through behavioral changes, reduced movement, and postural abnormalities
Hens with keel bone fractures spend more time in sedentary postures and show altered gait and posture
Genetics plays a role — some commercial laying hen lines have higher fracture rates than others
Perch design, height, and angle influence landing impact and fracture risk
The welfare comparison between keel bone fractures in cage-free systems and movement restriction in cages is genuinely contested

Welfare Considerations

Keel bone fractures represent the uncomfortable truth about cage-free egg production: the improvement in one welfare dimension (freedom of movement and behavioral expression) has been accompanied by the emergence of a significant welfare problem in another dimension. Birds with keel bone fractures experience chronic pain that affects their entire behavioral repertoire — not because of how they are housed in terms of space, but because of how that space is structured and how they interact with it. The industry and welfare science communities are actively working on solutions including perch design modifications, substrate improvements, genetic selection for bone strength, and lighting adjustments to reduce flock-level activity spikes that cause collision injuries.

What You Can Do

Support research into keel bone fracture prevention through organizations focused on laying hen welfare
Choose eggs from farms that report on keel bone fracture prevalence and have active reduction programs
Advocate for keel bone fracture monitoring to be included in cage-free certification scheme requirements
Support genetic selection research aimed at improving bone strength in commercial laying hen lines
Encourage egg producers to implement evidence-based perch design and installation guidelines that reduce fracture risk