The effect of piling behavior on the production and mortality of free-range laying hens

ABSTRACT: Piling, a dense cluster of hens, is a behavior of major concern to the cage-free egg industry. It can cause large numbers of mortalities at which point it is considered smothering. The aim of this study was to quantify whether piling can also have consequences on production and non-smother...

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Main Authors: David Armstrong, Lucy Asher, Ann Rayner, Halima Ngidda, Bryony Sharma, Helen Gray
Format: Article
Language:English
Published: Elsevier 2023-10-01
Series:Poultry Science
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S0032579123005084
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author David Armstrong
Lucy Asher
Ann Rayner
Halima Ngidda
Bryony Sharma
Helen Gray
author_facet David Armstrong
Lucy Asher
Ann Rayner
Halima Ngidda
Bryony Sharma
Helen Gray
author_sort David Armstrong
collection DOAJ
description ABSTRACT: Piling, a dense cluster of hens, is a behavior of major concern to the cage-free egg industry. It can cause large numbers of mortalities at which point it is considered smothering. The aim of this study was to quantify whether piling can also have consequences on production and non-smothering mortalities, which have not previously been described. Additionally, we aimed to describe characteristics of piling behavior relevant to for management. Video footage from 12 flocks of laying hens was analyzed for piling behavior across 3 wks. Production and mortality data were accessed using an integrated online management system. Bayesian linear mixed-effect models were used for formal statistical testing of the relationships between piling and production. Accounting for some missing data, a total of 252 d amounting to approximately 15,624 h were analyzed for the presence or absence of piling behavior, which we believe constitutes the largest analysis of piling behavior in the scientific literature to date. All flocks observed exhibited piling behavior even if they had no history of smothering. On average, flocks piled more than 4 times per day for around 44 min per event and the peak piling time occurred between 1300 and 1359. We found that the number of piling events was associated with a reduction in the number of eggs produced the next day; based on the average of 4 piles per day this amounted to 7.35 fewer eggs per 1,000 birds per day. Contrary to our hypothesis, we found total piling duration per day was positively associated with fewer Grade B eggs, with a decrease of 0.74 Grade B eggs for every hour of piling per day. No relationship was observed between piling and mortality not attributed to smothering. We discuss possible causes and explanations for these results including birds’ response to stress, crowd dynamics, and daily rhythms. Here we show the potential for piling behavior to have sublethal consequences on production even in the absence of smothering-related deaths.
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spelling doaj.art-96c0d515235b41fc80d2c1efd1956b862023-09-24T05:14:04ZengElsevierPoultry Science0032-57912023-10-0110210102989The effect of piling behavior on the production and mortality of free-range laying hensDavid Armstrong0Lucy Asher1Ann Rayner2Halima Ngidda3Bryony Sharma4Helen Gray5School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, United KingdomSchool of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, United Kingdom; Corresponding author:FAI Farms Ltd., The Barn, Wytham, Oxfordshire OX2 8QJ, United KingdomSchool of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, United KingdomSchool of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, United KingdomSchool of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, United KingdomABSTRACT: Piling, a dense cluster of hens, is a behavior of major concern to the cage-free egg industry. It can cause large numbers of mortalities at which point it is considered smothering. The aim of this study was to quantify whether piling can also have consequences on production and non-smothering mortalities, which have not previously been described. Additionally, we aimed to describe characteristics of piling behavior relevant to for management. Video footage from 12 flocks of laying hens was analyzed for piling behavior across 3 wks. Production and mortality data were accessed using an integrated online management system. Bayesian linear mixed-effect models were used for formal statistical testing of the relationships between piling and production. Accounting for some missing data, a total of 252 d amounting to approximately 15,624 h were analyzed for the presence or absence of piling behavior, which we believe constitutes the largest analysis of piling behavior in the scientific literature to date. All flocks observed exhibited piling behavior even if they had no history of smothering. On average, flocks piled more than 4 times per day for around 44 min per event and the peak piling time occurred between 1300 and 1359. We found that the number of piling events was associated with a reduction in the number of eggs produced the next day; based on the average of 4 piles per day this amounted to 7.35 fewer eggs per 1,000 birds per day. Contrary to our hypothesis, we found total piling duration per day was positively associated with fewer Grade B eggs, with a decrease of 0.74 Grade B eggs for every hour of piling per day. No relationship was observed between piling and mortality not attributed to smothering. We discuss possible causes and explanations for these results including birds’ response to stress, crowd dynamics, and daily rhythms. Here we show the potential for piling behavior to have sublethal consequences on production even in the absence of smothering-related deaths.http://www.sciencedirect.com/science/article/pii/S0032579123005084smotheringchickencrowdingwelfareegg
spellingShingle David Armstrong
Lucy Asher
Ann Rayner
Halima Ngidda
Bryony Sharma
Helen Gray
The effect of piling behavior on the production and mortality of free-range laying hens
Poultry Science
smothering
chicken
crowding
welfare
egg
title The effect of piling behavior on the production and mortality of free-range laying hens
title_full The effect of piling behavior on the production and mortality of free-range laying hens
title_fullStr The effect of piling behavior on the production and mortality of free-range laying hens
title_full_unstemmed The effect of piling behavior on the production and mortality of free-range laying hens
title_short The effect of piling behavior on the production and mortality of free-range laying hens
title_sort effect of piling behavior on the production and mortality of free range laying hens
topic smothering
chicken
crowding
welfare
egg
url http://www.sciencedirect.com/science/article/pii/S0032579123005084
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