Available online 6 May 2015
Perseveration in a guessing task by laying hens selected for high or low levels of feather pecking does not support classification of feather pecking as a stereotypy
Highlights
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- We hypothesised that feather pecking is a stereotypy.
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- Hens from a control as well as lines selected for high and low levels of feather pecking were used.
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- We tested the hypothesis by recording recurrent perseveration in a guessing task.
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- High feather pecking line birds had the lowest level of recurrent perseveration.
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- The hypothesis could not be supported by the data.
Abstract
Feather
pecking is a behaviour by which birds damage or destroy the feathers of
themselves (self-pecking) or other birds (allo feather pecking), in
some cases even plucking out feathers and eating these. The self-pecking
is rarely seen in domestic laying hens but is not uncommon in parrots.
Feather pecking in laying hens has been described as being stereotypic,
i.e. a repetitive invariant motor pattern without an obvious function,
and indeed the amount of self-pecking in parrots was found to correlate
positively with the amount of recurrent perseveration (RP), the tendency
to repeat responses inappropriately, which in humans and other animals
was found to correlate with stereotypic behaviour. In the present
experiment we set out to investigate the correlation between allo
feather pecking and RP in laying hens. We used birds (N = 92)
from the 10th and 11th generation (G10 and G11) of lines selectively
bred for high feather pecking (HFP) and low feather pecking (LFP), and
from an unselected control line (CON) with intermediate levels of
feather pecking. We hypothesised that levels of RP would be higher, and
the time taken (standardised latency) to repeat a response lower, in HFP
compared to LFP hens, with CON hens in between. Using a two-choice
guessing task, we found that lines differed significantly in their
levels of RP, with HFP unexpectedly showing lower levels of RP than CON
and LFP. Latency to make a repeat did not differ between lines. Latency
to make a switch differed between lines with a shorter latency in HFP
compared to LFP (in G10), or CON (in G11). Latency to peck for repeats
vs. latency to peck for switches did not differ between lines. Total
time to complete the test was significantly shorter in HFP compared to
CON and LFP. Thus, our hypotheses were not supported by the data. In
contrast, selection for feather pecking seems to induce the opposite
effects than would be expected from stereotyping animals: pecking was
less sequenced and reaction to make a switch and to complete the test
was lower in HFP. This supports the hyperactivity-model of feather
pecking, suggesting that feather pecking is related to a higher general
activity, possibly due to changes in the dopaminergic system.
Keywords
- Feather pecking;
- Laying hens;
- Genetic selection;
- Guessing task;
- Recurrent perseveration;
- Stereotyped behaviour
- Corresponding author. Tel.:
+49 05141 3846 123; fax: +49 05141 3846 117.
Copyright © 2015 Elsevier B.V. All rights reserved.
