Genetic and phenotypic correlations between duration of fertility and certain traits in Alexandria and Fayoumi chickens.

Two Alexandria lines selected for a high (HL) or low (LL) eight-week body weight, and an unselected Fayoumi line were used to study the duration of fertility, fertility percentage, fertility percentage duration, age at sexual maturity, egg number in the first ninety days of laying, egg weight, eight-week body weight, and body weight at sexual maturity. The fertility could be improved through selection for duration of fertility. Within the lines, early mature pullets had a longer duration of fertility than those matured later. The duration of fertility within the lines is a rather good indicator of eight-week body weight. Within the lines, the duration of fertility increases with the increase in body weight at the age of sexual maturity.