Reflective properties of domestic fowl (Gallus g. domesticus), the fabric of their housing and the characteristics of the light environment in environmentally controlled poultry houses

Abstract

1. The light intensity and spectral power distribution in 3 broiler and 6 layer houses were sampled and converted to a measure which takes account of the domestic fowl's spectral sensitivity (termed lux corrected). Light intensity was highly variable around the layer houses (mean 33.2, s.d. 37.7 lux (corrected)) and to a lesser extent in the broiler houses (mean 5.2, s.d. 2.2 lux (corrected)). The mean intensities were also very much lower than on a sunny, June day at midday at Silsoe (42,937 lux (corrected)) and of different power distributions. 2. The reflectivity of the plumage of 15 traditional breeds of domestic fowl was surveyed. Most feathers showed a characteristic pattern of reflectivity , increasing either side of a wavelength of λ=400 nm. In 13 breeds the tail and wing feathers were darker than the breast and back feathers. Reflectivity at λ=700 nm was a good predictor of reflectivity at λ=320 nm. Food, bedding, wood and skin all had similar reflectivities to feathers. Metal, plastic and rubber all had more constant reflectivities across the spectrum. 3. The reflectivities of the fresh, feathered carcases of 3 male broilers (Cobb) and 3 layer hens (ISA Brown) were measured. There were small changes in hue and saturation within and between individual carcases, even for the apparently white broiler chickens. 4. Photographs were taken, with and without a UVA-only pass filter, of a broiler cock (Cobb), layer hen (ISA Brown) and cock jungle fowl. No additional patternation was evident in the UVA-only photographs and the jungle fowl lost most of its ornamentation. The texture of bare skin was enhanced in the UVA-only photographs. 5. The implications of these results for poultry behaviour are discussed.