Breed characterization of native chickens based on their head shape and size

Abstract

Native chickens have unique characteristics related to adaptation to the most diverse breeding systems. The phenotypic characterization of different chicken ecotypes is necessary in view of the current situation of loss of local genetic resources. Development of methodologies capable of supporting morphometric studies is very useful in native domestic breeds conservation. Thus, geometric morphometrics  is a recently proposed approach for the quantification of shape and size variation separately, which has shown advantages over the traditional method. The objective of this study was to characterize female chickens of the Peloco, Barbuda, and Caneluda breeds based on their head shape and size by using geometric morphometric. Images of the head of 85 chickens were captured, and 13 landmark and semi-landmark were set in the beak, nostril and eye regions. The three chicken breeds evaluated showed significant differences (p < 0.01) regarding the head shape. Most variations occurred in the eyes and beak; the Peloco breed presented wide and curved beak, and round eyes. According to the grouping analysis, the Peloco and Caneluda breeds had similar head shape and were allocated to the same group; and the Barbuda breed was allocated separated from the others by differing from them. The breeds presented significant differences (p < 0.01) in size, and the Caneluda breed had the largest head size. The geometric morphometrics allowed the distinction of the breeds by identifying shape variations, especially in the beak and eye regions. Thus, it is promising for studies on phenotypic diversity and breed characterization of these birds.