CNRS, IFCE, INRAE, UMR PRC, Université de Tours, Nouzilly, France.
CNRS, IFCE, INRAE, UMR PRC, Université de Tours, Nouzilly, France.
Poult Sci. 2024 Jul;103(7):103813. doi: 10.1016/j.psj.2024.103813. Epub 2024 Apr 30.
Individual differences in free-range chicken systems are important factors influencing how birds use the range (or not), even if individuals are reared in the same environmental conditions. Here, we investigated how various aspects of the birds' behavioral and cognitive tendencies, including their optimism/pessimism, cognitive flexibility, sociability, and exploration levels, are associated with range use and how they may change over time (before and after range access). To achieve this, 100 White Leghorn laying hen chicks underwent three distinct behavioral/cognitive tests-the cognitive bias test, the detour test, and the multivariate test-prior to gaining access to the range, between 9 and 39 days of age. After range access was allowed (from day 71), birds' range use was evaluated over 7 nonconsecutive days (from 74-91 days of age). Subsequently, a subset of birds, classified as high rangers (n = 15) and low rangers (n = 15) based on their range use, underwent retesting on the same three previous tests between 94 and 108 days of age. Our results unveiled a negative correlation trend between birds' evaluation of the ambiguous cue and their subsequent range use (rho = -0.19, p = 0.07). Furthermore, low rangers were faster to learn the detour task (χ2 = 7.34, df = 1, p = 0.006), coupled with increased sociability during the multivariate test (rho = -0.23, p = 0.02), contrasting with their high-ranging counterparts, who displayed more exploratory behaviors (F[1,27] = 3.64, p = 0.06). These behavioral patterns fluctuated over time (before and after range access); however, conclusively attributing these changes to birds' aging and development or the access to the range remains challenging. Overall, our results corroborate that behavioral and cognitive individual differences may be linked to range use and offer novel perspectives on the early behavioral and cognitive traits that may be linked to range use. These findings may serve as a foundation for adapting environments to meet individual needs and improve animal welfare in the future.
个体差异是影响鸡只使用围场（或不使用）的重要因素，即使它们在相同的环境条件下饲养。在这里，我们研究了鸟类行为和认知倾向的各个方面，包括它们的乐观/悲观、认知灵活性、社交性和探索水平，如何与围场使用相关，以及它们如何随时间变化（在获得围场使用权之前和之后）。为了实现这一目标，100 只白来航蛋鸡雏鸡在获得围场使用权之前（9 至 39 日龄）接受了三种不同的行为/认知测试——认知偏差测试、绕道测试和多元测试。在获得围场使用权后（71 日龄后），在 7 个非连续的日子里（91 日龄前）评估鸡只的围场使用情况。随后，根据围场使用情况，将一部分鸡（高围场组 n=15，低围场组 n=15）分为高围场组和低围场组，在 94 至 108 日龄时再次接受这三个先前测试。我们的结果揭示了鸟类对模糊线索的评估与其随后的围场使用之间呈负相关趋势（rho=-0.19，p=0.07）。此外，低围场组在学习绕道任务时更快（χ2=7.34，df=1，p=0.006），在多元测试中表现出更高的社交性（rho=-0.23，p=0.02），这与高围场组形成对比，高围场组表现出更多的探索行为（F[1,27]=3.64，p=0.06）。这些行为模式随时间波动（在获得围场使用权之前和之后）；然而，将这些变化归因于鸟类的衰老和发育或围场的使用权仍然具有挑战性。总的来说，我们的结果证实了行为和认知上的个体差异可能与围场使用有关，并为与围场使用相关的早期行为和认知特征提供了新的视角。这些发现可以为未来适应环境以满足个体需求和提高动物福利奠定基础。
