Effect of phenotype (plumage colour) on egg weight and live weight of backyard hen

The objective of the study was to determine the effect of phenotype on body weight (BW) and egg weight (EW) from the backyard hen (BH) (Gallus gallus domesticus) in the Bajio region of Michoacan, Mexico. 101 BH (one/town = six/municipality) randomly selected were used, and one egg/BH analyzed. Plumage colour (PCo), BW and EW was recorded. The compositional analysis of crop content/BH provided information on the feed/BH. Statistical analysis was performed by categorical models and generalised linear models. The PCo of the BH ranged from the uniformity (red, brown, black, white, yellow and gray), to mixtures of these. PCo ratios were affected by the municipality (P < 0.001). The municipality of Jose Sixto Verduzco presented the total observed range of PCo. The predominated PCo was red (29.2 %) (P 10 < 0.05), followed by brown (20.4 %); the black PCo came in 4th place (16.1 %). The average BW was 1.567 +/- 0.316 kg. Average affected by the municipality (P < 0.001). The BH with the red PCo were the lightest: 1.484 kg (P < 0.05). The EW was 51 +/- 4 g and was affected by the municipality (P < 0.001). The BH with the black PCo had lower egg weight: 49 g (P < 0.05). The current phenotypes (PCo) of BH are highly variable and this affects its BW and EW. The introduction of genotypes that are different from the autochthonous does not necessarily improve the BW and EW indicators.