Examining the catching, carrying, and crating process during depopulation of end-of-lay hens

Abstract

Summary: Laying hen flocks undergo depopulation at end of lay, a difficult process that has been associated with injuries and is considered stressful to hens and human collectors. To date, most assessments of depopulations have been conducted within cage housing systems, layers, or noncage broilers, thus offering little relevance to noncage laying hen systems including aviaries. Given that the predominant housing systems in Switzerland are multitier aviaries and their growing popularity in general, our study was undertaken to establish a baseline for hen injuries and stress as well as the experience of human workers during depopulation. For the effort, a total of 15 individual farms were visited, and a battery of assessments was made on a total of 603 individual end-of-lay hens. In addition, potentially influential factors such as time of day, handling duration, or time into depopulation were recorded and analyzed. The results suggest that approximately 8.1% of hens sustain severe injuries (i.e., fractures and muscle damage) or exhibit a considerable stress reaction (i.e., increased corticosterone levels), whereas 90% of laying hens are only mildly affected.

Keywords

• depopulation
• laying hen
• animal welfare
• fracture
• stress
• fearfulness