Social aggressiveness, pecking at hands, and its relationships with tonic immobility duration and heterophil to lymphocyte ratio in chickens of different breeds
Two different experiments were conducted in order to study the relationships between social aggressiveness, pecking at experimenter hands, and two indicators of stress (heterophil to lymphocyte ratio, and tonic immobility duration) in several breeds of chickens. Experiment 1 measured the relative social aggressiveness of cocks based on dominant-subordinate paired encounters, whereas Experiment 2 analyzed pecking of hens towards experimenter hands while managed. No significant correlation was found between cock relative aggressiveness and heterophil to lymphocyte ratio or tonic immobility duration. Cocks from the White-faced Spanish and Black Menorca breeds, selected for large size earlobes, were the most aggressive, whereas cocks from breeds selected for egg production (White Leghorn, Black Castellana, and Buff Prat) were the least aggressive. Hens pecking or no pecking at experimenter hands did not differ significantly for heterophil to lymphocyte ratio, although hens pecking hands had significantly shorter tonic immobility duration, suggesting that this behavior is associated with less fearfulness. © Verlag Eugen Ulmer GmbH & Co. Stuttgart.
| Main Authors: | , , |
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| Format: | journal article biblioteca |
| Language: | eng |
| Published: |
2005
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| Online Access: | http://hdl.handle.net/20.500.12792/5646 |
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