The objective of the present study was to examine the details of dynamic changes of behaviour of brooded and non-brooded chicks at an early age, the effects of broody hens on the behavioural development and fearfulness of chicks and the correlation between maternal care and fearfulness of chicks, as seen in mice. Five groups of five chicks each were reared by a broody hen, and five groups of five chicks each were provided with a red heating lamp for 28 days. The behaviour of all chicks was recorded using scan sampling at 5-min intervals for 6 h per day at 1, 5, 9, 13, 17, 21 and 25 days of age. Two behavioural tests for evaluating fearfulness and familiarity with humans were conducted at 27 and 28 days of age, and the duration of freezing and latency to the first vocalisation and first step, as well as the number of vocalisations and steps during 10 min, were recorded. The data were analysed using repeated-measures analysis of variance (ANOVA) or Student's t-test. Although the brooded chicks spent 60% of their time resting under broody hens at 1 day of age, the proportion then decreased sharply during the first 2 weeks, stabilised around 10% from 13 days of age and, finally, was reduced to almost zero at 25 days of age. The brooded chicks spent more time on active behaviour (P<0.05), dust-bathing (P<0.01) and floor pecking (P<0.01), but less time on gentle feather pecking (P<0.01) than non-brooded chicks. In both behavioural tests, the total duration of freezing was shorter in brooded chicks (P<0.001) and the total number of vocalisations (P<0.001) and steps taken (P<0.001) were higher in brooded chicks. No correlation between resting under broody hens and fearfulness was found. In conclusion, the behavioural development of chicks was promoted and fearfulness was decreased markedly by the presence of a broody hen.
|Publication Title||Applied Animal Behaviour Science|
|Author Address||Laboratory of Animal Behaviour and Management, Department of Animal Science and Biotechnology, Faculty of Veterinary Medicine, Azabu University, 1-17-71 Fuchinobe, Sagamihara, Kanagawa 229-8501, Japan.email@example.com|
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