Sexual maturity and related phenomena in the domestic fowl

Abstract

Three hundred and eighty-two Fayomi pullets were available from different hatches throughout the year. The age and body weight, as well as the weight of first eggs at sexual maturity in relation to growth curves, were recorded. The fertilizability and hatchability of the first eggs laid at sexual maturity were also examined from one hundred pullets hatched during the months of November and August.1. (a) The winter hatches (December, January and February) reached sexual maturity at 183 days and at a body weight of 1093 g. The weight of the first ten eggs was 31·8 g., while the period from first to the tenth egg was 26 days. Summer hatches (June, July and August) reached sexual maturity at 165 days and at a body weight of 1124 g., while the weight of the first ten eggs was 32·4 g. and the period from first to tenth egg was 31 days. Autumn hatches (September, October and November) reached sexual maturity at 159 days and at a body weight of 1023 g., while the weight of the first ten eggs was 31·4 g. and the period from first to tenth egg was 23 days.(b) Summer and winter hatches attained sexual maturity at an older age and heavier body weight, and laid heavier first ten eggs in a longer period than autumn hatches.2. The growth curves were higher for the summer hatches than for the spring (March, April and May) ones. Winter and autumn hatches were intermediate. Summer hatches attained sexual maturity at a higher relative growth rate than autumn and winter hatches. In Egypt (30° N.), the effect of temperature seems to override that of daylength in respect to growth and sexual maturity.3. Yearly differences in the attainment of sexual maturity were significant, mainly in December hatches. Individual differences were minimized during summer hatches.4. (a) The first egg laid can be fertilizable and even hatchable. When sexual maturity was attained at an old age or a heavy body weight, the first eggs laid had a greater chance of being fertilizable and hatchable. This is due to the weight of first eggs laid and to the season at which sexual maturity is attained.(b) The attainment of sexual maturity as measured by the fertilizability and hatchability of first eggs, seems to be a gradual phenomenon.