Uniformity group and age had a highly significant effect on cracked eggs, mortality, fertility and percent hatched of total eggs set (Table 3). There was no clear trend in the percentage of eggs hatched and fertility despite the fact that there were significant differences between uniformity groups (Table 4). The lack of trend in fertility with uniformity groups inspite of significance can be explained in terms of the natural mating used in these flocks as opposed to artificially inseminated hens in other reports. In natural mating sexual unresponsiveness by females and/or preferential mating by the males were probable reasons for intermittent periods of infertility.