Foraging Behavior Shows Individual-Consistency Over Time, and Predicts Range Use in Slow-Growing Free-Range Male Broiler Chickens

Abstract

Recent research on free-range chickens shows that individual behavioral differences may link to range use. However, most of these studies explored individual behavioral differences only at one time point or during a short time window, assessed differences when animals were out of their social group and home environment (barn and range), and in specific tests or situations. Therefore, it is yet unclear how different behaviors relate to range use and how consistent these behaviors are at the individual level. To fill this gap, we here aimed to describe the behavioral budget of slow-growing male broiler chickens (S757N) when in their social group and home environment during the whole rearing period (from the second week of life to the twelfth week, before slaughter), and to relate observed behavioral differences to range use. For this, we followed a sample of individuals in two flocks (n = 60 focal chickens out of 200 chickens per flock), over two seasons, during three periods: before range access (from 14 to 25 days old), during early range access (first weeks of range access, from 37 to 53 days old), and during late range access (last weeks of range access, from 63 to 87 days old). By the end of each period, individual tests of exploration and social motivation were also performed, measuring exploration/activity and sociability propensities. Our results show that foraging (i.e., pecking and scratching at the ground) was the only behavior that correlated to range use for all three rearing periods, independent of the season. Foraging was also the only behavior that showed within-individual consistency from an early age and across the three rearing periods. Foraging may, therefore, serve as a useful behavioral predictor of range use in free-range broiler chickens. Our study increases the knowledge of how behaviors develop and relate to each other in a domesticated and intensely selected species, and improves our understanding of the biology of free-range broiler chickens. These findings can, ultimately, serve as a foundation to increase range use and improve chicken welfare.

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

“…Specifically, a negative correlation was observed between the willingness to approach conspecifics during a social motivation test and range use, while foraging behavior exhibited a positive correlation with range use ( Ferreira et al, 2020a ; Ferreira et al, 2021a ). However, it is noteworthy that these findings did not consistently hold true across different stages of bird development and for different strains ( Ferreira et al, 2022 ; Bonnefous et al, 2023 ). In the case of laying hens, a few studies investigated how birds’ exploratory and fear tendencies before range access may be related to range use.…”

“…Each of these assessments was conducted on the same individuals both before and after the birds gained access to the range to compare how these variables change over time. Building upon previous research, we hypothesized that an optimistic environmental perception, exploratory behaviors, especially foraging behavior, and spatial cognition would correlate positively with range use ( Campbell et al, 2018a ; Ferreira et al, 2021a ; Hedlund et al, 2021 ; Ferreira et al, 2022 ; Taylor et al, 2023 ). Conversely, we anticipated a negative correlation between range use, cognitive flexibility and social motivation ( Ferreira et al, 2020a; 2020c ).…”

Adaptability Challenges for Organic Broiler Chickens: A Commentary

“…Foraging involves pasture and kinetic attitudes. Ferreira et al [ 85 ] found that that the foraging of chickens was correlated to range use from an early age and during all of the rearing periods, independent of the season. According to their study, foraging was the only behavior that showed within-individual consistency, and therefore may serve as a useful behavioral predictor of range use in free-range broiler chickens.…”

“…Indeed, Ferreira et al [ 86 ] have shown that chickens have stable ranging behavior over time, and that the chickens defined as high rangers had less capacity to improve their spatial memory than low rangers when submitted to successive spatial tests. Furthermore, high rangers of a slow-growing chicken strain forage more than the low rangers, with individual consistency over time [ 85 ]. The low rangers were also more prone to be near their near conspecifics than high rangers during social motivation tests [ 87 ].…”

Performance, meat quality and blood parameters in four strains of organic broilers differ according to range use

“…Nevertheless, a high variability of outdoor range use is often reported between ocks [4][5][6] . Several studies in chickens showed that range use differs between individuals and is consistent within an individual over time and across contexts or situations 7,8 , therefore qualifying ranging behaviour as a potential personality trait 9 .…”