Perch access for laying hens is essential for bone health, natural roosting behavior, and welfare, with perch design and placement affecting whether hens actually benefit from this provision.
Perch provision is a welfare improvement over barren battery cages, but its value depends entirely on quality of implementation. Perches set too close to the cage wall or to each other cannot be used comfortably. Birds falling from poorly designed perches sustain keel bone fractures — a painful injury that affects a substantial proportion of hens in enriched colony and even free-range systems. Round perches reduce keel bone fracture rates compared to square perches. The welfare gap between systems with nominal perch provision and systems with genuinely welfare-positive perch design is substantial. Outcome-based monitoring of keel bone fracture prevalence provides a direct measure of how well perch systems are serving their welfare purpose.