Effect of intermingled rearing of different breeds and bird density on fluctuating asymmetry in laying hens

The purpose of this study was to analyze the effect of intermingling and bird density on the fluctuating asymmetry of laying hens. Three Spanish breeds and a White Leghorn population were used. In experiment 1, cocks were reared in four treatments from 8 to 20 wk of age separated at a density of 20 birds/m2, intermingled at a density of 20 birds/m2, intermingled at a density of 12 birds/m2, and intermingled at a density of 4 birds/m2. Intermingling and bird density were significant for the fluctuating asymmetry of toe length in the four breeds (P < 0.01) and the fluctuating asymmetry of leg length in the White Leghorn (P < 0.05). The fluctuating asymmetry of cocks with intermingled rearing at a density of 20 birds/m2 was larger than that of cocks with separated rearing, and cocks reared with a density of 20 birds/m2 had larger relative asymmetry than cocks reared with densities of 12 and 4 birds/m2. There were no significant differences for the fluctuating asymmetry of leg width, wattle length, and the combined value of the five traits, and was opposite to that which would be expected for the asymmetry of wing length in the White Leghorn. In experiment 2, hens were reared in three different treatments from 8 to 20 wk of age separated at a density of 4 birds/m2, intermingled at a density of 12 birds/m2, and intermingled at a density of 20 birds/m2. The simultaneous effect of intermingling and bird density was significant for the fluctuating asymmetry of leg length and toe length (P < 0.01), wattle length and leg width (P < 0.05), and the combined relative asymmetry of the five traits (P < 0.001) in the four breeds, and the fluctuating asymmetry of wing length in the Red-Barred Vasca and the White Leghorn (P < 0.01). Hens with intermingled rearing and a density of 20 birds/m2 had always larger relative asymmetry than hens with separated rearing and a density of 4 birds/m2.

Bibliographic Details

Main Authors:	Campo, J. L., García Dávila, Sara, Gil, M. G.
Format:	journal article biblioteca
Language:	English
Published:	Verlag Eugen Ulmer 2010
Online Access:	http://hdl.handle.net/20.500.12792/5633 http://hdl.handle.net/10261/293210
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