DEVELOPMENTAL STABILITY IN RELATION TO POPULATION-DENSITY AND BREED OF CHICKENS GALLUS-GALLUS

Bilaterally symmetrical morphological characters with fluctuating asym metry usually have small, random deviations from symmetry that reflect the ability of individuals to cope with genetic and environmental str ess. A comparison of the level of fluctuating asymmetry in two fast-gr owing breeds (ScanBrid, Ross 208) with that of a slow-growing breed (L a Belie Rouge) and wild jungle fowl from India revealed a positive rel ationship between growth rate and asymmetry. Fast-growing chickens kep t at three densities (20, 24, and 28 chickens per square meter) reveal ed a positive association between fluctuating asymmetry and density. L arge individuals generally had higher levels of fluctuating asymmetry than small individuals. Tonic immobility, which is often used as a mea sure of fearfulness, was weakly positively associated with the degree of fluctuating asymmetry (P < .05). Measures of fluctuating asymmetry may provide information on levels of stress experienced by domesticate d animals.