Work

Behavioral predictors of outdoor range use in slow-growing naked-neck male broiler chickens: The role of social context

Year: 2026

Type: article

Abstract: This study investigated whether behavioral traits expressed early in life predict subsequent range use in slow-growing male broilers and whether social context modulates the expression of these traits. Across two successive flocks (n = 220 birds per flock), individuals were assessed using three complementary paradigms: a cognitive bias test, an exploration test conducted both in isolation and in trios, and an attention bias test performed after range access under both isolation and paired conditions. Individual range use was measured using an index based on repeated scans that recorded how frequently and how far each bird used the outdoor range. Principal component analysis of exploration behavior before range access identified an activity–exploration axis and a fearfulness–vigilance axis. Activity–exploration scores positively predicted subsequent range use, whereas fearfulness-related behaviors did not. Birds tested in trios were more exploratory/active and less vigilant than when tested alone, indicating strong social modulation of behavior. After range access, behavioral differences between high and low rangers became particularly evident under social conditions: high rangers maintained stable activity levels across contexts, whereas low rangers showed reduced activity in trios. In contrast, range-use phenotype was not associated with cognitive judgement bias or attention bias responses. Although birds discriminated stimuli, neither approach behavior in the cognitive bias test nor reaction to alarm calls in the attention bias test differed between high and low rangers. Social context, however, reduced vigilance responses in the attention bias test, consistent with social buffering effects. Overall, early exploratory tendencies, but not affective biases, predict outdoor range use in slow-growing broilers. These findings highlight the importance of assessing behavioral traits in ecologically relevant social contexts when investigating inter-individual variation in free-range systems.

Source: Applied Animal Behaviour Science

DOI: 10.1016/j.applanim.2026.107161

Authors: Caroline Germain, Vanessa Guesdon, Ludovic Calandreau, Karine Germain, Vitor Hugo Bessa Ferreira

Institutions: Université de Tours, Centre National de la Recherche Scientifique, Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement, Physiologie de la Reproduction et des Comportements, JUNIA

Language: English

Topic: Animal Behavior and Welfare Studies

Subfield: Animal Science and Zoology

Field: Agricultural and Biological Sciences

Domain: Life Sciences

Open Access status: hybrid

Estimated APC paid: $3,220

Funders: Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement, HORIZON EUROPE Framework Programme