Laying Hen Keel Bone Fractures | Animal Welfare Hub

Keel bone fractures affect the majority of laying hens in cage-free and free-range systems — a largely hidden welfare crisis that undermines the benefits of moving away from conventional cages.

Key Facts

The keel bone is the central breastbone to which flight muscles attach — it is the most commonly fractured bone in laying hens
Prevalence of keel bone fractures ranges from 50–80% in free-range and aviary systems — higher than in conventional enriched cages
Most fractures occur when hens jump or fall from elevated perches and landing structures — poor perch design and height are key risk factors
Hens with fractured keels show altered movement patterns, reluctance to perch, and reduced access to resources — indicating that fractures cause pain
Current UK and EU welfare codes do not mandate keel bone fracture monitoring as a welfare outcome indicator
Selective breeding for heavy breast muscle has made keel bones structurally weaker, increasing fracture risk in modern high-producing breeds
Welfare-conscious design features — lower perch heights, ramps, padded landing areas — can reduce but not eliminate fracture prevalence

Welfare Considerations

Keel bone fractures represent one of the most significant unresolved welfare problems in modern laying hen production. The irony is that systems promoted as high welfare — free-range and aviary — have higher fracture rates than conventional cages because they provide height and perching opportunities that hens use, but fall from. This does not mean cage systems are better — they prevent fractures by denying hens the freedom of movement that causes them. The solution is better-designed systems that allow natural behaviour without the injury risk, combined with selective breeding for stronger skeletal structure. The welfare gap between what is claimed and what is delivered in "cage-free" eggs is real and needs industry attention.

What You Can Do

Advocate for keel bone fracture prevalence to be included as a mandatory welfare outcome measure in farm assurance schemes
Support research into perch design and building features that reduce fracture risk in aviary and free-range systems
When choosing eggs, look beyond the headline "free-range" or "cage-free" label to schemes with specific welfare outcome requirements
Support selective breeding research aimed at producing hens with stronger keel bones without sacrificing other welfare traits
Engage with industry bodies and retailers on the keel bone problem — it is beginning to receive the attention it deserves
Reduce egg consumption overall — the per-egg welfare footprint is better with fewer, higher-welfare eggs
Support Compassion in World Farming and RSPCA in their campaigns for evidence-based, outcome-focused poultry welfare standards