Performance of laying hens in a cognitive bias task : effect of time since change of environment
In the debate on laying hen welfare, and specifically housing conditions, the main focus has been on physiological and behavioural measures. What is lacking is knowledge of how the hen experiences the situation – her state of mind. This study is an attempt to gain insight into the private mental sta...
| Autor principal: | |
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| Formato: | M2 |
| Lenguaje: | Inglés sueco |
| Publicado: |
SLU/Dept. of Animal Environment and Health (until 231231)
2010
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| Materias: |
| _version_ | 1855570234457456640 |
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| author | Lindström, Lena |
| author_browse | Lindström, Lena |
| author_facet | Lindström, Lena |
| author_sort | Lindström, Lena |
| collection | Epsilon Archive for Student Projects |
| description | In the debate on laying hen welfare, and specifically housing conditions, the main focus
has been on physiological and behavioural measures. What is lacking is knowledge of how
the hen experiences the situation – her state of mind.
This study is an attempt to gain insight into the private mental states of former battery
hens. It uses a cognitive bias method based on spatial judgement, i.e. judgement of a
ambiguous stimulus placed spatially in between a reinforced and an unreinforced stimulus.
This method has previously shown differences in judgement by animals in enriched versus
poor housing. The aim of the current study was to measure such biases expressed by hens
two months compared to four months after moving from battery cages to littered pens. The
animals were also tested in a novel object task for a measure on general anxiety, and their
plumage condition was scored. Their social rank was established by testing penmates in
pairwise competitions over a limited food resource.
The hens showed longer latencies to reach the intermediate position four months after
leaving the cages, compared to two months after. Possible reasons for this could be that the
positive effects of the improved environment were largest when the hens had recently left
the battery cages, with the effect of the improvement gradually being diminished or even
reversed. It is likely that novelty in itself is positive to hens, and a static environment
becomes boring in time even though it is far more complex than a battery cage.
No difference was found in the reactions to ambiguous cues by hens of different social
status. A strong correlation was found between feather score and social dominance.
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| format | M2 |
| id | RepoSLU863 |
| institution | Swedish University of Agricultural Sciences |
| language | Inglés swe |
| publishDate | 2010 |
| publishDateSort | 2010 |
| publisher | SLU/Dept. of Animal Environment and Health (until 231231) |
| publisherStr | SLU/Dept. of Animal Environment and Health (until 231231) |
| record_format | eprints |
| spelling | RepoSLU8632012-04-20T14:11:14Z Performance of laying hens in a cognitive bias task : effect of time since change of environment Lindström, Lena cognitive bias laying hen gallus gallus animal behaviour animal welfare In the debate on laying hen welfare, and specifically housing conditions, the main focus has been on physiological and behavioural measures. What is lacking is knowledge of how the hen experiences the situation – her state of mind. This study is an attempt to gain insight into the private mental states of former battery hens. It uses a cognitive bias method based on spatial judgement, i.e. judgement of a ambiguous stimulus placed spatially in between a reinforced and an unreinforced stimulus. This method has previously shown differences in judgement by animals in enriched versus poor housing. The aim of the current study was to measure such biases expressed by hens two months compared to four months after moving from battery cages to littered pens. The animals were also tested in a novel object task for a measure on general anxiety, and their plumage condition was scored. Their social rank was established by testing penmates in pairwise competitions over a limited food resource. The hens showed longer latencies to reach the intermediate position four months after leaving the cages, compared to two months after. Possible reasons for this could be that the positive effects of the improved environment were largest when the hens had recently left the battery cages, with the effect of the improvement gradually being diminished or even reversed. It is likely that novelty in itself is positive to hens, and a static environment becomes boring in time even though it is far more complex than a battery cage. No difference was found in the reactions to ambiguous cues by hens of different social status. A strong correlation was found between feather score and social dominance. I djurskyddsdebatten runt värphönor och hur de hålls har fokus huvudsakligen legat på fysiologiska faktorer och mätbara beteenden. Däremot saknas kunskap om hur hönan själv upplever sin situation, hennes inre tillstånd. Den här studien är ett försök att få tillträde till de privata mentala upplevelserna hos före detta burhönor. Metoden som används går ut på att se hur en höna tolkar ett tvetydigt stimulus, som ligger spatiellt mellan två inlärda stimuli; en belönad och en obelönad. Metoden har tidigare visat att djur som lever i berikade jämfört med oberikade miljöer bedömer sådana stimuli olika. Den här studien jämför bedömningarna hos hönor som flyttat från konventionella, oinredda burar till ströade boxar, två och fyra månader efter flytten. Hönornas reaktion på ett främmande föremål testades för att mäta deras allmänna nervositet, och deras fjäderdräkt bedömdes. Deras dominanstatus fastställdes genom parvis konkurrens över en begränsad födoresurs. Hönorna tog längre tid på sig att nå den mittersta positionen fyra månader jämfört med två månader efter flytten. Detta kan bero på att den positiva effekten av miljöbytet var störst kort efter flytten, och därefter gradvis jämnades ut eller till och med omvändes. Det verkar troligt att förändring i sig är positivt för hönor, och att en statisk miljö blir tråkig med tiden, även om den är mycket mer komplex än en konventionell bur. Ingen skillnad hittades i reaktionerna på tvetydiga signaler hos hönor med olika social status. Det fanns en stark korrelation mellan befjädring och rang. SLU/Dept. of Animal Environment and Health (until 231231) 2010 M2 eng swe https://stud.epsilon.slu.se/863/ |
| spellingShingle | cognitive bias laying hen gallus gallus animal behaviour animal welfare Lindström, Lena Performance of laying hens in a cognitive bias task : effect of time since change of environment |
| title | Performance of laying hens in a cognitive bias task : effect of time since change of environment |
| title_full | Performance of laying hens in a cognitive bias task : effect of time since change of environment |
| title_fullStr | Performance of laying hens in a cognitive bias task : effect of time since change of environment |
| title_full_unstemmed | Performance of laying hens in a cognitive bias task : effect of time since change of environment |
| title_short | Performance of laying hens in a cognitive bias task : effect of time since change of environment |
| title_sort | performance of laying hens in a cognitive bias task : effect of time since change of environment |
| topic | cognitive bias laying hen gallus gallus animal behaviour animal welfare |