Keel Bone Fractures in Laying Hens: A Pervasive Welfare Problem

Keel bone fractures affect a majority of laying hens in many housing systems and represent one of the most significant unresolved welfare problems in commercial egg production globally.

Key Facts

The keel bone is the large ridge of the sternum to which flight muscles attach — it is a structurally important and well-innervated bone
Prevalence studies find keel bone fractures in 50-80% of laying hens in aviary and barn systems, and lower but significant rates in cages
Fractures most commonly occur from collisions with perches, dividers, and housing structures during flight and landing
Fractured keel bones cause acute pain at the time of fracture and ongoing chronic pain as the bone remodels incorrectly
Hens with keel bone fractures show reduced activity, altered perching behaviour, and pain-associated postural changes
Genetic selection for bone quality and perch design improvements are the most promising preventive strategies
Despite the scale of the problem, keel bone fractures receive far less regulatory attention than other hen welfare issues

Welfare Considerations

Keel bone fractures are now recognised as one of the most significant chronic pain conditions in commercial egg production. Acute fractures cause immediate pain detectable in behaviour, vocalisation, and stress physiology. The subsequent healing process in commercial conditions — where hens cannot rest the bone adequately — often results in callus formation and chronic deformity that causes ongoing discomfort for the remainder of the bird's laying life. The irony is that enriched systems introduced to improve welfare (aviaries, barn systems with perches) are associated with higher fracture rates than cage systems, because increased flight opportunities create more collision risk. This does not argue for returning to cages — the welfare gains from space and enrichment outweigh fracture risk — but it does demand serious investment in prevention through genetics, perch design, and housing management.

What You Can Do

Support egg producers investing in perch design research and genetic selection to reduce keel bone fractures
Choose eggs from farms that monitor and report keel bone fracture rates as part of welfare assessment
Advocate for keel bone fracture prevalence to be included in welfare certification scheme requirements
Support research into pain management for laying hens with keel bone fractures
Engage with retailers to ask how they are addressing keel bone welfare in their egg supply chains
Donate to poultry welfare organisations researching solutions to this widespread but neglected problem