Effect of laying month on egg quality in the Utrerana chicken breed (Partridge variety) during the first laying period.

Abstract

The Utrerana chicken is an endangered egg-producing breed native to Spain with four feather varieties that display productive seasonality. To fill the gap in knowledge on the seasonal variation in egg quality, 378 eggs were collected during the entire first laying period, between March and August, from an experimental flock of hens of the Partridge variety of the Utrerana breed and subsequently analysed to assess the effect of the laying month on external and external egg quality traits. The eggs, with an average weight of 61.66 g and sharp shape (shape index: 70.77), had 31.64% yolk, 56.59% albumen, and 11.77% white-coloured shell 0.43 mm in thickness. The egg yolk was light orange in colour (Roche fan score: 10.56) with a yolk index of 37.78%, whereas the albumen was moderately firm (Haugh units: 69.12). The egg yield was seasonal and peaked in the second month of the laying period, with a hen-day egg production of 61.4%. Throughout the first laying period, egg weight and eggshell content remained invariable and yolk content increased, whereas its quality and colour intensity worsened, and albumen content and quality decreased as a consequence of aging and increasing ambient temperature. In conclusion, the Partridge variety of the Utrerana chicken breed can be considered suitable for alternative farming systems because it lays good-quality eggs at a moderate seasonal laying rate.