Managing Free-Range Laying Hens - Part B: Early Range Users Have More Pathology Findings at the End of Lay but Have a Significantly Higher Chance of Survival - An Indicative Study

Abstract

While free-range laying hens frequently experience health and welfare challenges, the contribution of range use towards these risks are largely unknown. The aim of this pilot study was to investigate the survival, health and welfare of commercial free-range laying hens and explore the association with early range use. Range use of 9375 Lohmann Brown hens housed within five flocks was assessed during 18–21 weeks of age and individual hens were classified as "rangers" (frequent range users), "roamers" (intermittent range users), and "stayers" (rare/no range users) were then subject to necropsy at 74 weeks of age. Rangers and roamers were three times and 2.4 times more likely to survive than stayers, respectively (<i>p</i> = 0.001). Overall, rangers had significantly better feather cover and more lesions associated with spotty liver diseases compared to roamers and stayers (<i>p</i> = 0.001). Similarly, rangers and roamers had a higher prevalence of <i>A. galli</i> infection and less frequent signs of fatty liver syndrome compared to stayers. Rangers had a higher proportion of hens with full ovary follicle production compared to stayers and roamers (<i>p</i> = 0.035). This information is highly relevant to consider the targeted support of different flock subpopulations to improve hen health and welfare, directly affecting farm profitability. Further research on other farms is warranted to investigate the transferability of the observed results.