Laying Hen Perch Use and Keel Bone Welfare in Commercial Systems

Perches are a fundamental requirement for laying hens, but their design and placement critically affects both use rates and keel bone fracture risk. Getting perch design right is one of the most important welfare details in egg production.

Key Facts

Perching is a strong natural behaviour in hens derived from ancestral roosting behaviour to avoid ground predators
Access to perches is required in enriched colony cages and alternative systems under EU Directive 1999/74/EC
Keel bone fractures — affecting over 50% of hens in some systems — are linked to perch use: hens fall from or collide with perches during roosting
Round perch profiles cause more keel injuries than oval or flattened profiles that allow stable grip
Perch height significantly affects keel fracture risk: perches above 45 cm increase collision frequency during landing
The timing of perch introduction matters: pullets trained to use perches during rearing show better spatial coordination as adults
Infrared thermography and pressure mat studies show that comfortable perch design increases use rates and reduces nocturnal disturbance injuries

Welfare Considerations

Perch design is a case study in unintended welfare consequences: the requirement for perches was introduced to improve welfare, but poorly designed perches generate keel bone fractures that cause chronic pain. The balance between providing perch access and minimising injury requires attention to profile, height, placement, and pullet training. Hens with keel fractures show behavioural signs of pain including reluctance to use perches, altered postures, and reduced activity — yet continue to use perches because the roosting drive is so strong. Welfare-positive perch design reduces but does not eliminate fracture risk; the underlying cause — selection for high lay rates that compromises skeletal integrity — requires breed-level solutions. Meanwhile, evidence-based perch design standards represent an achievable, practical welfare improvement within existing systems.

What You Can Do

Choose eggs from producers with documented keel bone monitoring programmes using perch design evidence
Support research into pullet perch training programmes and optimal perch geometry for keel bone health
Ask certification schemes whether they specify perch design standards beyond simple provision requirements
Advocate for mandatory keel bone fracture monitoring at slaughter with farm-level reporting requirements
Donate to hen welfare research organisations working on skeletal health in commercial laying hens