Laying Hen Welfare: Keel Bone Fractures

The significant welfare problem of keel bone fractures in laying hens in cage-free systems and what research shows about prevention and management.

Key Facts

Keel bone fractures affect 50-80% of hens in some cage-free aviary systems, making it one of the most prevalent welfare problems in modern egg production
Fractures occur from collisions with perches and structures during flight or landing, particularly in inexperienced young hens entering aviary systems
Fractured keels cause chronic pain evidenced by changes in movement, reduced perch use, and altered pain sensitivity tests in affected hens
Selective breeding for keel bone strength and appropriate bone mineralization can reduce fracture prevalence in genetically susceptible lines
Aviary design modifications including perch angle, height, and surface texture reduce collision and fracture risk significantly
Low-density conventional cages have lower keel fracture rates than aviaries, creating a welfare paradox for cage-free transition advocates

Welfare Considerations

Keel bone fractures represent an unresolved welfare crisis in cage-free egg production that deserves far more attention than it typically receives in welfare certification and consumer communication. The widely-held assumption that cage-free always equals better welfare is complicated by keel fracture data — while cage-free systems address behavioral deprivation from conventional cages, they introduce a different welfare problem in the form of chronic bone pain from fractures. The solution is not to return to cages but to address keel bone welfare through better aviary design, genetic selection, and management practices. The welfare bar for cage-free certification should explicitly include keel bone fracture monitoring and management as a requirement, not an afterthought.

What You Can Do

Support egg producers and certification schemes that explicitly monitor and report keel bone fracture prevalence in their flocks
Ask welfare certification bodies why keel bone fracture rates are not required reporting metrics in most cage-free certification standards
Support research into aviary design modifications and genetics that reduce keel bone fracture rates in commercial laying hen populations
Recognize that cage-free eggs do not automatically mean high welfare and look for additional welfare indicators beyond cage status
Reduce egg consumption overall or choose eggs from smaller flocks with lower stocking densities where keel bone management is more feasible