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Ontogenetic determinants of feather pecking in laying hens

Lindhout, R. (2000) Ontogenetic determinants of feather pecking in laying hens. Master's Thesis / Essay, Biology.

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Abstract

The development of feather pecking was studied in relation to laying background, social rearing condition and coping style in two strains of white leghorns (Gal/us domesiicus) that differ in their propensity to feather peck and in stress response. The strain with a high propensity to feather peck (high feather peckers or HP) reacts with a strong cathecholamine response to manual restraint whereas the strain with a low propensity to feather peck (low feather peckers or LP) reacts with a high corticosterone response. The development of feather pecking was recorded in two experimental conditions: a semicommercial and a semi-natural condition. In the semi-commercial condition chicks hatched from commercially produced eggs were raised in a large group without a mother. In the seminatural condition chicks hatched from eggs produced by small groups of free-ranging hens were raised in small broods by a (foster) mother. Both strains were represented in both treatments by four replicates. Over the course of twenty weeks pecking frequencies were scored on average once a week for thirty minutes per cage on individually marked hens and roosters. During the first four weeks there was no effect of housing condition, but high feather peckers showed more feather pecking then the low feather peckers. From week five to twenty the effect of strain persisted and an effect of condition became visible: semi-natural chicks showed less feather pecking then semi-commercial ones. This was especially apparent in the HP-strain. To separate the effect of housing condition from laying and social rearing backgrounds one male and one female of each group were reallocated to one new cage after four weeks. The strain difference in feather pecking observed in the first four weeks disappeared; there was also no difference in feather pecking between the former semi-natural and semi-commercial chicks. The housing conditions therefore did not have a persistent effect on feather pecking. The high peckers feather pecked less after reallocation. It seemed that the presence of low peckers 'diluted the feather pecking: they did not join it and that probably inhibited the high peckers. We also found correlations between social pecking and feather pecking. From these and other results we conclude that feather pecking has an important social component. In a standard stress test (open-field) we found a persistent effect of rearing condition on how individuals behave. Semi-naturally raised chicks behaved less inhibited than semicommercially reared chicks. Most remarkable was the difference in righting time in a tonic immobility test performed six weeks after reallocation: the semi-naturally reared chicks had a shorter righting time than the semi-commercially reared chicks. At twenty weeks after hatching the reallocation period was repeated with the female focal chicks from the home cages. No differences in feather pecking were found between the four groups then. The strong differences between the groups that had been found in coping in the open field and tonic immobility tests during the first reallocation period had disappeared in the second reallocation period. Semi-natural housing conditions seem to have a diminishing effect on feather pecking, but this effect is not persistent after changing these conditions. The feather pecking by high peckers decreases after reallocation, probably because of the presence of low peckers. Housing conditions do have a persistent effect on stress responses, which are a part of coping style, at least until nine weeks of age. Semi-natural circumstances apparently help the chicks to be less inhibited in coping with stress factors. To solve the problems caused in poultry farms by feather pecking it is probably necessary to keep the groups small and to let a (foster) mother raise the chicks. We have not found a relation between Feather pecking and coping with stress.

Item Type: Thesis (Master's Thesis / Essay)
Degree programme: Biology
Thesis type: Master's Thesis / Essay
Language: English
Date Deposited: 15 Feb 2018 07:31
Last Modified: 15 Feb 2018 07:31
URI: http://fse.studenttheses.ub.rug.nl/id/eprint/9225

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