Layer Hen Bone Health and Welfare

Osteoporosis and bone fractures are among the most significant welfare problems for laying hens, driven by the metabolic demands of high egg production and inadequate exercise opportunities.

Key Facts

Modern laying hens produce approximately 300 eggs per year, each requiring 2g of calcium
Up to 30% of hens in battery cage systems have fractured bones at the time of slaughter
Medullary bone — a calcium reservoir — is depleted faster than it can be replenished in high-production breeds
Keel bone fractures affect 50-80% of hens in all housing systems including cage-free and free-range
Keel bone fractures cause measurable pain evidenced by altered posture, reduced activity, and analgesic preference
Perches that are improperly designed contribute to keel bone damage during landing
Genetic selection for high egg production has inadvertently reduced bone strength in laying breeds

Welfare Considerations

Bone health represents a systemic welfare failure across the laying hen industry, affecting birds in all housing systems. The metabolic priority given to egg shell calcification means skeletal calcium is chronically depleted. Fractures — particularly of the keel bone — cause chronic pain that persists for weeks or months, altering behavior, reducing feed intake, and affecting quality of life throughout a significant portion of the laying cycle. Welfare improvements require both housing redesign (better perch landing surfaces, appropriate perch height) and genetic selection for bone strength alongside production traits. Consumer pressure for welfare-certified eggs can drive farm-level investment in these improvements.

What You Can Do

Choose eggs certified under high-welfare standards that require enriched housing or free range
Support research into bone-healthy laying hen genetics through organizations like the Roslin Institute
Advocate for mandatory keel bone fracture monitoring in national laying hen welfare regulations
Engage supermarkets to require keel bone reporting from their egg suppliers
Reduce egg consumption or shift to plant-based alternatives to decrease overall demand pressure