Plumage colour and feather pecking in laying hens, a chicken perspective?

Abstract

1. This study investigated whether feather damage due to feather pecking and bird behaviour were influenced by plumage colour in Oakham Blue laying hens (black, white, grey colour variants). The reflectance properties of feathers and spectral composition of light environments experienced by the hens were also examined.

2. Nine hundred and seventy-nine birds were inspected and scored for feather damage; 10·5 h of video recordings were examined to record feather pecking and bird behaviour. Feathers and light environments were measured using a USB-2000 spectrometer and DH-2000-CAL-DTH lamp.

3. Oakham Blue birds with white plumage had less feather damage due to feather pecking than black or grey birds. There was more severe feather pecking in the mornings than in the afternoon. White birds feather pecked severely more than black or grey birds, although there were no other behavioural differences between plumage colours.

4. White feathers reflected at a higher intensity than black or grey feathers. However, black and grey feather spectra were relatively flat and the contribution of UV wavelengths to plumage reflection was proportionally greater than that for white feathers.

5. Light intensity inside a poultry house was 100 × (UW/cm²/nm) less than on the range and there was low or no UV reflectance. Under the dim, artificial lights inside a poultry house, Oakham Blue hens with black and grey feathers may be less visible to conspecifics than white birds because their plumage reflects at a lower intensity. Furthermore, the lack of available UV light inside vs. outside and the higher contribution of UV reflectance to black and grey plumage may make black and grey birds appear more different inside the house than white birds. It is possible that this novel/unusual appearance may make black or grey Oakham Blue hens more susceptible to feather pecking.

Acknowledgements

Thanks to Food Animal Initiative and Dean's Foods Ltd for access to birds. A. Parker provided spectrometer equipment. Dean's Foods Ltd and The Worshipful Company of Poulter's Charitable Trust provided financial assistance. A. Bright was supported by a TAD Scholarship from the New Zealand Government. M.S. Dawkins and T.A. Jones and an anonymous reviewer commented on earlier drafts of this manuscript.