Assimetria flutuante como indicador de estresse ambiental em galinhas caipiras brasileiras.

Fluctuating asymmetry (FA) is a technique that, based on the measurement of discrete or continuous characteristics on both sides of the individual, aims to assess whether ontogenetic development has been affected by external stressors. Stress in chickens can trigger several problems, from cannibalism to premature termination of laying, affecting animal welfare and productivity. Thus, the objective was to investigate the existence of FA in the shape and size of the head of native birds of the Peloco, Caneludo do Catolé and Canela Preta genetic groups and commercial lineage CBC, as well as to identify whether the environment and the rearing system can be considered stressors for birds. Birds from the three native genetic groups, as well as birds from the commercial lineage CBC showed FA in head shape and size, probably related to the environment, especially to chronic heat stress, given the high temperatures of the rearing environment. As for the birds of the Peloco genetic group, there was a greater sensitivity to stress when kept in confinement, as the males of this group raised in an intensive system showed undesirable social behavior, such as cannibalism. [ABSTRACT FROM AUTHOR]