Stress during Commercial Hatchery Processing Induces Long-Time Negative Cognitive Judgement Bias in Chickens

Worldwide, billions of laying hen chicks are incubated and processed under highly industrialised circumstances every year, which, as we have previously shown, has long-lasting effects. Here, we measured corticosterone incorporated in down feathers to investigate possible stress during the incubation...

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Main Authors: Louise Hedlund, Tiphaine Palazon, Per Jensen
Format: Article
Language:English
Published: MDPI AG 2021-04-01
Series:Animals
Subjects:
Online Access:https://www.mdpi.com/2076-2615/11/4/1083
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author Louise Hedlund
Tiphaine Palazon
Per Jensen
author_facet Louise Hedlund
Tiphaine Palazon
Per Jensen
author_sort Louise Hedlund
collection DOAJ
description Worldwide, billions of laying hen chicks are incubated and processed under highly industrialised circumstances every year, which, as we have previously shown, has long-lasting effects. Here, we measured corticosterone incorporated in down feathers to investigate possible stress during the incubation and showed that commercially incubated chicks did not have elevated levels of feather corticosterone, which implies that the main part of the stress effects from hatchery originates from the perinatal period and the handling immediately post-hatch. Further, we investigated how the early hatchery stress affects the chicks’ cognitive welfare state, i.e., “optimism” and “pessimism”. We exposed commercially hatched chickens to a positive cue, an aversive cue and ambiguous cues. The birds were tested at 1 and 10 w of age and the behaviour was compared with that of non-stressed chicks. Latencies to approach ambiguous cues were longer for the stressed chicks, both at 1 (<i>p</i> = 0.008) and at 10 (<i>p</i> = 0.020) weeks of age, i.e., these showed a more pessimistic-like behaviour. We conclude that the main part of the stress effects in commercially hatched chicks originates in the perinatal period, and further, that these birds show lasting levels of increased pessimism. This strongly indicates a long-time poorer welfare state for the animals.
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spelling doaj.art-a284e51280cc4cc682c84bd33e5f797b2023-11-21T15:00:42ZengMDPI AGAnimals2076-26152021-04-01114108310.3390/ani11041083Stress during Commercial Hatchery Processing Induces Long-Time Negative Cognitive Judgement Bias in ChickensLouise Hedlund0Tiphaine Palazon1Per Jensen2Institution of Physics, Chemistry and Biology, Linköping University, 58183 Linköping, SwedenInstitution of Physics, Chemistry and Biology, Linköping University, 58183 Linköping, SwedenInstitution of Physics, Chemistry and Biology, Linköping University, 58183 Linköping, SwedenWorldwide, billions of laying hen chicks are incubated and processed under highly industrialised circumstances every year, which, as we have previously shown, has long-lasting effects. Here, we measured corticosterone incorporated in down feathers to investigate possible stress during the incubation and showed that commercially incubated chicks did not have elevated levels of feather corticosterone, which implies that the main part of the stress effects from hatchery originates from the perinatal period and the handling immediately post-hatch. Further, we investigated how the early hatchery stress affects the chicks’ cognitive welfare state, i.e., “optimism” and “pessimism”. We exposed commercially hatched chickens to a positive cue, an aversive cue and ambiguous cues. The birds were tested at 1 and 10 w of age and the behaviour was compared with that of non-stressed chicks. Latencies to approach ambiguous cues were longer for the stressed chicks, both at 1 (<i>p</i> = 0.008) and at 10 (<i>p</i> = 0.020) weeks of age, i.e., these showed a more pessimistic-like behaviour. We conclude that the main part of the stress effects in commercially hatched chicks originates in the perinatal period, and further, that these birds show lasting levels of increased pessimism. This strongly indicates a long-time poorer welfare state for the animals.https://www.mdpi.com/2076-2615/11/4/1083animal welfarelaying henshatcherycorticosteroneearly stresscognitive judgement bias
spellingShingle Louise Hedlund
Tiphaine Palazon
Per Jensen
Stress during Commercial Hatchery Processing Induces Long-Time Negative Cognitive Judgement Bias in Chickens
Animals
animal welfare
laying hens
hatchery
corticosterone
early stress
cognitive judgement bias
title Stress during Commercial Hatchery Processing Induces Long-Time Negative Cognitive Judgement Bias in Chickens
title_full Stress during Commercial Hatchery Processing Induces Long-Time Negative Cognitive Judgement Bias in Chickens
title_fullStr Stress during Commercial Hatchery Processing Induces Long-Time Negative Cognitive Judgement Bias in Chickens
title_full_unstemmed Stress during Commercial Hatchery Processing Induces Long-Time Negative Cognitive Judgement Bias in Chickens
title_short Stress during Commercial Hatchery Processing Induces Long-Time Negative Cognitive Judgement Bias in Chickens
title_sort stress during commercial hatchery processing induces long time negative cognitive judgement bias in chickens
topic animal welfare
laying hens
hatchery
corticosterone
early stress
cognitive judgement bias
url https://www.mdpi.com/2076-2615/11/4/1083
work_keys_str_mv AT louisehedlund stressduringcommercialhatcheryprocessinginduceslongtimenegativecognitivejudgementbiasinchickens
AT tiphainepalazon stressduringcommercialhatcheryprocessinginduceslongtimenegativecognitivejudgementbiasinchickens
AT perjensen stressduringcommercialhatcheryprocessinginduceslongtimenegativecognitivejudgementbiasinchickens