Perch use in laying hens improves bone strength, reduces keel bone fracture risk, and satisfies natural roosting motivation. Perch provision and design are key factors in cage-free welfare.
Perch provision is both a welfare good in itself — satisfying the roosting motivation that hens express even under selection pressure — and a preventive measure against the pervasive welfare problem of keel bone fractures. Hens that exercise by using perches develop stronger skeletons, particularly around the keel bone that bears the greatest mechanical load. However, design matters enormously: perches must be at adequate height, appropriate width, and spaced to allow simultaneous use by multiple birds. Overcrowded perches cause aggression and may exclude subordinate individuals. Aviary systems with well-designed multi-level perching and ramp access show the best bone health outcomes.