A systematic review of the effect of perch height on keel bone fractures, deformation and injuries, bone strength, foot lesions and perching behavior in layer hens has been published by the European Food Standards Agency (EFSA). 

EFSA notes that there remains a lack of clarity around the height and design of perches where layer behavioral needs are concerned. Similarly, there may be negative bird welfare implications resulting from inappropriate perch design and height.

The report offers a summary of four systematic reviews. Scientific data was examined to assess which perch height and design would satisfy European Union legal requirements and could be considered adequate from a welfare point of view, both in enriched and alternative systems. 

The review sought to identify to which degree a minimum and maximum height and the position of the perch are important factors in layer welfare. Additionally, it sought to identify design criteria for perches, including material, shape and length, all of which may influence bird welfare. From this an assessment was made of which design is best suited to satisfy birds’ behavioral needs without negatively impacting their health.