van Staaveren Nienke, Ellis Jennifer, Baes Christine F, Harlander-Matauschek Alexandra
Centre for the Genetic Improvement of Livestock, Department of Animal Biosciences, University of Guelph, Guelph, Ontario, Canada N1G 2W1; The Campbell Centre for the Study of Animal Welfare, Department of Animal Biosciences, University of Guelph, Guelph, Ontario, Canada N1G 2W1.
Centre for Nutrition Modelling, Department of Animal Biosciences, University of Guelph, Guelph, Ontario, Canada N1G 2W1.
Poult Sci. 2021 Feb;100(2):397-411. doi: 10.1016/j.psj.2020.11.006. Epub 2020 Nov 19.
Feather pecking (FP) is a significant issue in laying hens, which impacts societal acceptance of poultry farming, farm productivity, and bird welfare. Environmental enrichment-modifications of the environment to stimulate biological functioning and psychological well-being of animals-is one management strategy farmers can use to mitigate FP. However, inconsistent results of environmental enrichment are reported across studies questioning its value. A meta-analysis was used to determine the effect of environmental enrichment on FP and feather damage (FD) in laying hens. A systematic review of published literature from 4 databases resulted in 23 publications that met inclusion criteria. Feather pecking and FD outcomes were standardized between studies using different scoring systems. Driving variables included the presence of enrichment, production period when the enrichment started, housing type, beak trimming, bird strain, and age of the birds when FP and FD was measured. Considering the experiment as a random effect, linear mixed model analysis was used in a 2-step approach, whereby variables with a P < 0.30 in univariate analysis were included within the subsequent multivariate analysis. Variables with P < 0.05 in the multivariate analysis were retained in the final models. Model selection and evaluation were based on corrected Akaike information criteria, the root mean square prediction errors, and concordance correlation coefficients. A higher frequency of FP was observed in flocks lacking enrichment (P < 0.001), with increased age (P = 0.001), and in cage housing systems (P = 0.002). Similarly, FD increased in flocks lacking enrichment (P = 0.018), with increased age (P < 0.001), in the absence of beak trimming (P = 0.001) and in cage housing systems (P = 0.042). This meta-analysis confirmed the effectiveness of environmental enrichment in reducing FP and FD. Nevertheless, the modest ability of enrichment to dampen FD (-0.14 ± 0.06, 1-4 scale) suggests that other management strategies must be implemented in conjunction with environmental enrichment to successfully manage FP and resulting FD.
啄羽行为（FP）是蛋鸡养殖中的一个重要问题，它影响着社会对家禽养殖的接受度、农场生产力以及鸡的福利。环境富集——即对环境进行改造以刺激动物的生物功能和心理健康——是养殖户可用来减轻啄羽行为的一种管理策略。然而，各项研究报告的环境富集效果并不一致，这对其价值提出了质疑。本研究采用荟萃分析来确定环境富集对蛋鸡啄羽行为和羽毛损伤（FD）的影响。通过对4个数据库中的已发表文献进行系统回顾，最终得到23篇符合纳入标准的出版物。使用不同评分系统的研究之间，啄羽行为和羽毛损伤结果进行了标准化处理。驱动变量包括是否存在富集、富集开始时的生产阶段、饲养类型、断喙情况、鸡的品种以及测量啄羽行为和羽毛损伤时鸡的年龄。将实验视为随机效应，采用线性混合模型分析分两步进行，即在单变量分析中P<0.30的变量纳入后续的多变量分析。多变量分析中P<0.05的变量保留在最终模型中。模型选择和评估基于校正后的赤池信息准则、均方根预测误差和一致性相关系数。在缺乏富集的鸡群中（P<0.001）、随着鸡龄增加（P=0.001）以及在笼养系统中（P=0.002），观察到啄羽行为的频率更高。同样，在缺乏富集的鸡群中（P=0.018）、随着鸡龄增加（P<0.001）、未进行断喙处理时（P=0.001）以及在笼养系统中（P=0.042），羽毛损伤增加。这项荟萃分析证实了环境富集在减少啄羽行为和羽毛损伤方面的有效性。然而，富集减轻羽毛损伤的能力有限（-0.14±0.06，1 - 4级），这表明必须结合其他管理策略与环境富集措施，才能成功管理啄羽行为及其导致的羽毛损伤。
