Farmed Hen Bone Health: Osteoporosis and Fracture Prevention

Osteoporosis and bone fractures are among the most significant welfare problems in laying hens, caused by calcium mobilization for eggshell production that weakens the skeleton over time.

Key Facts

Modern laying hens produce 300+ eggs per year compared to 12-30 in wild jungle fowl ancestors
Calcium for eggshell production is mobilized from skeletal reserves, progressively weakening bones
End-of-lay hens may have severe osteoporosis with fracture rates exceeding 50% in some systems
Fractures cause chronic pain that is often unrecognized due to stoic behavior in poultry
Genetic selection for bone density and calcium metabolism can reduce fracture rates
Appropriate dietary calcium provision throughout lay reduces but does not eliminate the problem

Welfare Considerations

Laying hen bone disease represents a welfare cost written into the biology of modern egg production. The calcium demands of producing over 300 eggs annually exceeds what dietary provision alone can meet — the skeleton becomes a calcium reservoir that is progressively depleted. End-of-lay hens often have brittle bones that fracture during normal movement, transport, and handling. Pain from these fractures persists throughout the remainder of the laying cycle. Addressing this requires both genetic approaches and nutritional management, but fundamentally reflects the welfare cost of extreme production levels driven by selective breeding.

What You Can Do

Support welfare standards that require bone health assessment and monitoring in laying hens
Choose eggs from slower-producing heritage breeds where available
Advocate for genetic welfare assessment to include bone health alongside production traits
Learn about laying hen physiology to understand the systemic welfare costs of egg production