{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,28]],"date-time":"2026-09-28T20:09:21Z","timestamp":1790626161420,"version":"4.1.0"},"reference-count":73,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2021,8,12]],"date-time":"2021-08-12T00:00:00Z","timestamp":1628726400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Poultry Science Association","award":["Arthur W. Perdue Fellowship"],"award-info":[{"award-number":["Arthur W. Perdue Fellowship"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Animals"],"abstract":"<jats:p>Barren housing and high stocking densities may contribute to negative affective states in broiler chickens, reducing their welfare. We investigated the effects of environmental complexity and stocking density on broilers\u2019 attention bias (measure of anxiety) and tonic immobility (measure of fear). In Experiment 1, individual birds were tested for attention bias (n = 60) and in Experiment 2, groups of three birds were tested (n = 144). Tonic immobility testing was performed on days 12 and 26 (n = 36) in Experiment 1, and on day 19 (n = 72) in Experiment 2. In Experiment 1, no differences were observed in the attention bias test. In Experiment 2, birds from high-complexity pens began feeding faster and more birds resumed feeding than from low-complexity pens following playback of an alarm call, suggesting that birds housed in the complex environment were less anxious. Furthermore, birds housed in high-density or high-complexity pens had shorter tonic immobility durations on day 12 compared to day 26 in Experiment 1. In Experiment 2, birds from high-density pens had shorter tonic immobility durations than birds housed in low-density pens, which is contrary to expectations. Our results suggest that birds at 3 weeks of age were less fearful under high stocking density conditions than low density conditions. In addition, results indicated that the complex environment improved welfare of broilers through reduced anxiety.<\/jats:p>","DOI":"10.3390\/ani11082383","type":"journal-article","created":{"date-parts":[[2021,8,12]],"date-time":"2021-08-12T10:54:41Z","timestamp":1628765681000},"page":"2383","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":61,"title":["Effect of Environmental Complexity and Stocking Density on Fear and Anxiety in Broiler Chickens"],"prefix":"10.3390","volume":"11","author":[{"given":"Mallory G.","family":"Anderson","sequence":"first","affiliation":[{"name":"Department of Animal and Poultry Sciences, Virginia Tech, Blacksburg, VA 24061, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Andrew M.","family":"Campbell","sequence":"additional","affiliation":[{"name":"Department of Animal and Poultry Sciences, Virginia Tech, Blacksburg, VA 24061, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4485-5740","authenticated-orcid":false,"given":"Andrew","family":"Crump","sequence":"additional","affiliation":[{"name":"Centre for Philosophy of Natural and Social Science, London School of Economics and Political Science, London WC2A 2AE, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Gareth","family":"Arnott","sequence":"additional","affiliation":[{"name":"School of Biological Sciences, Queen\u2019s University Belfast, Belfast BT9 5DL, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5238-6959","authenticated-orcid":false,"given":"Ruth C.","family":"Newberry","sequence":"additional","affiliation":[{"name":"Department of Animal and Aquacultural Sciences, Faculty of Biosciences, Norwegian University of Life Sciences, 1432 \u00c5s, Norway"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3799-5078","authenticated-orcid":false,"given":"Leonie","family":"Jacobs","sequence":"additional","affiliation":[{"name":"Department of Animal and Poultry Sciences, Virginia Tech, Blacksburg, VA 24061, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2021,8,12]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"229","DOI":"10.1016\/0168-1591(95)00616-Z","article-title":"Environmental enrichment: Increasing the biological relevance of captive environments","volume":"44","author":"Newberry","year":"1995","journal-title":"Appl. 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