The present project was planed to study the effect of mating ratio and age on fertility and hatchability in Japanese quails.

The production of fertile eggs was found to relate to the number of males present in a flock. Fertility and hatchability of eggs was directly influenced by sex ratio and age of birds. However, very little information in this regard is available.

One hundred and seventy four males and four hundred twenty six females quails of 4 weeks age were purchased from the local market. They were divided into five equal mating groups i.e. A, B, C, D and E comprising 120 quails in each group. Each group was further divided into 2 sub groups i.e. Al, A2, Bi, B2, Cl, C2, Dl, D2 and El, E2. The mating ratio of males and females in the respective groups was 1:1, 1:2, 1:3, 1:4 and 1:5. Birds were reared for a period of two weeks i.e. 5-6 weeks of age under similar environments on floor, then they were transferred to battery cages and were kept there upto the age of 16 weeks.

To assess the ideal parental age for optimal fertility and hatchability, hatching eggs from a single hatch breeding flock between 7 and 16 weeks of age were set twice in a week The mean hatching performance of the eggs set during 7 to 8, 9 to 10, 11 to 12, 13 to 14 and 15 to 16 weeks of age were recorded separately.

The unhatched eggs were opened on the day 18 and examined
macroscopically to identify the infertile eggs, embryonic mortality, fertility and hatchability of fertile eggs set were calculated.

Identical environmental and managemental conditions were provided to all the experimental birds. They were fed on commerca1 ration -libitum. Clean and fresh water was made available at all times. Light was provided 24 h during rearing time and 16 h during breeding period. Standard rearing, breeding and hatching management procedures were followed throughout the study period.

The following data was recorded:
Weight of birds at the start of experiment, Feed consumption, Average body weightlbirds on weekly basis, Feed conversion ratio, Mortality if any, Fertility percentage and Hatchability percentage.

The data collected was statistically analysed using 5 x 5
Factorial design.

The quail chicks at 4 weeks age weighed on an average 98 gm/bird and within a period of two weeks rearing gained on an average a body weight of 134.1 gm/bird. The weight gradually increased with age. The final body weight at the age week 16, under ratio 1:1, 1:2, 1:3, 1:4 and 1:5 was 130.5, 186.5, 188.0, 189.5, 191.5 and 193.5 gm respectively, the overall mean value being 189.8 gm/bird.
The difference in average weight/bird in various groups has been due to the difference in the number of females. The females weighed heavier than the males consequently the groups having smaller number of females were lighter in weight than the groups having higher number of females.

The percentage weekly increase in body weight was 37.6, 12.76 and 8.27% at age weeks 7, 8 and 9 respectively. Further increase in body weight from age week 10 to 16, ranged between 0.9 and 4.7. The rearing of Japanese quail beyond age weeks 8 or 9 for meat purposes will not be economical. The egg fertility was the highest at age weeks 13-14 (80.73%) followed by 15-16 (72.34%) 11-12 (7 1.12%), 9-10 (63.57%) and 7-8 weeks (56-20%), all being statistically different from one another. The mating ratio (1:1 to 1:5) showed statistically significant effect on egg fertility, which ranged between 58.16 to
8 1.12%, the maximum being at mating ratio of 1:2 and the minimum at 1:5.

The mating ratio and age have been found to have significant effect on egg hatchability, it was maximum at age weeks 13-14 (67.46%) and the minimum at age weeks 7-8 (41-23%). Similarly mating ratio 1:2 resulted in the maximum (66.08) and mating ratio 1:5 showed the minimum (48.73%) egg hatchability.

The results of present study have led to the conclusion that egg fertility and hatchability were highest at age week 13-14 and at mating ratio 1:2.