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A meta-analysis on the effect of environmental enrichment on feather pecking and feather damage in laying hens

van Staaveren, N. and Ellis, J. and Baes, C. F. and Harlander-Matauschek, A.

Poult Sci (2021) 100: 397–411

DOI: 10.1016/j.psj.2020.11.006

Abstract

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 \textless 0.30 in univariate analysis were included within the subsequent multivariate analysis. Variables with P \textless 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 \textless 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 \textless 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.

Citation

van Staaveren, N., Ellis, J., Baes, C. F., & Harlander-Matauschek, A. (2021). A meta-analysis on the effect of environmental enrichment on feather pecking and feather damage in laying hens. Poult Sci, 100(2), 397–411. https://doi.org/10.1016/j.psj.2020.11.006 *Feathers/injuries, *Housing, Animal, abnormal behavior, abnormal behaviour, age differences, animal behavior, animal behaviour, Animal Behaviour [LL300], animal housing, animal rights, animal welfare, Animal Welfare, Animal Welfare [LL810], Animals, behavior, Behavior, Animal/*physiology, birds, chicken housing, chickens, Chickens/*physiology, data analysis, data banks, databases, debeaking, deviant behaviour, domesticated birds, effects, efficacy, Egg Producing Animals [LL130], egg production, enrichment, environmental factors, evaluation, Farm and Horticultural Structures [NN300], farmers, farming, feather pecking, Female, flocks, fowls, hens, housing, injurious pecking, literature reviews, livestock farming, meta-analysis, models, Models, Theoretical, multivariate analysis, Non-communicable Diseases and Injuries of Animals [LL860], plumage, poultry, poultry farming, productivity, publications, research, risk factors, studies, systematic reviews, trimming

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