Farmed Laying Hen Bone Health and Osteoporosis

Osteoporosis and bone fractures are among the most prevalent and serious welfare problems in laying hens, affecting millions of birds regardless of housing system.

Key Facts

Laying hens divert calcium from structural bone to eggshell production, resulting in progressive structural bone loss (osteoporosis) as the laying period advances.
Keel bone fractures affect 50-80% of laying hens in most housing systems including free-range and barn systems, not just cages.
Hens with fractured keel bones show behavioral changes consistent with chronic pain including reluctance to move, altered posture, and reduced resource use.
Exercise opportunities early in life - during rearing - are critical for building the bone density that determines fracture susceptibility during lay.
Breed selection is increasingly recognized as important: some commercial breeds show significantly lower keel bone fracture rates than others at equivalent production levels.

Welfare Considerations

Keel bone fractures represent one of the most underappreciated welfare problems in poultry, affecting hens across all housing systems. The shift from cage to non-cage systems improved welfare in many respects but did not resolve keel bone fractures and may in some cases have increased them due to collision injuries during perching. Good welfare requires a multi-factorial approach: appropriate breed selection, good rearing environments that encourage early bone development, perch design that minimizes collision risk, and monitoring of fracture prevalence as a welfare metric. Consumer campaigns and retailer commitments that focus solely on cage-free housing without addressing bone health leave a significant welfare gap.

What You Can Do

Support research into keel bone fracture causes and prevention across housing systems.
Ask egg producers and retailers what monitoring they do for keel bone fracture prevalence.
Advocate for breed welfare criteria that include bone health performance measures.
Engage with welfare certification standards to include keel bone health monitoring requirements.