The proportion of unhatched eggs that were apparently fertile or apparently infertile are given in Table 2. There were significantly more apparently infertile eggs than apparently fertile eggs (P < 0.0002). The proportion of unhatched eggs that were apparently infertile among the total eggs incubated increased with increasing length of pre-incubation storage (r = 0.95; P < 0.0001 and r = 0.91; P < 0.0001, respectively). No egg stored for 18 days or more was found to be apparently fertile.