Associations of range use with individual behaviour, clinical welfare indicators, fear response and gastrointestinal characteristics of two laying hen hybrids

Early and late cognitive and behavioral aspects associated with range use in free-range laying hens (Gallus gallus domesticus)

“…Similarly, for free-range laying hens, high range use was associated with better plumage, fewer comb wounds, shorter nail length, higher spleen and gizzard weight, but lower body weight, fat, and muscle ( Bari et al, 2020 ). Furthermore, outdoor preferring individuals were less fearful compared to indoor preferring ones during open-field tests ( Campbell et al, 2016 , 2019 a; but see Wurtz et al, 2023 where contrasting findings on two laying hen hybrids indicate that while behavior and gastrointestinal variables correlated with the extent of range use, fear levels, and several clinical welfare indicators did not). Overall, these findings reveal that while animals are provided with the choice and opportunity to access a larger and enriched space—the range, presumed to improve their welfare—some may opt not to use it due to potential fearfulness and/or negative cognitive perceptions.…”

“…Beyond these challenges, a concern in free-range chicken production revolves around the presence of within-flock inter-individual variability in the use of the range: chickens may exhibit varying levels of motivation to venture outside the barn and use the range. Notably, this variability in range use has been observed to lead to distinct zootechnical and welfare outcomes, even though individuals within a flock are raised under virtually identical conditions ( Bari et al, 2020 ; Sibanda et al, 2020 ; Taylor et al, 2020 ; Wurtz et al, 2023 ). For example, free-range broiler chickens that made frequent visits further from the barn had lower body weight, but better gait scores and reduced corticosterone in response to handling and confinement, compared to their indoor-preferring counterparts ( Taylor et al, 2020 ).…”