Effect of temporary transfers to 14 h on age at first egg in domestic pullets reared on 8-h photoperiods

Abstract

1.	Brown-egg pullets were reared on 8-h photoperiods and temporarily transferred at 80 d of age to 14-h photoperiods for 2, 4, 6, 8, 10 or 12 d. Controls were either maintained on 8 h or permanently transferred to 14 h at 80 d.
2.	Pullets given 8 or 12 long days matured 8–9 d earlier than constant 8-h controls, but 22–23 d later than pullets transferred permanently to long days. Mean age at first egg for the groups given 2, 4, 6 or 10 d of 14-h days were not significantly different from the 8-h controls. The mean weight of first egg and body weight at first egg for the temporarily-photostimulated groups were not significantly different from constant 8-h controls, but egg weights were ≥5·1 g and body weights at first egg ≥200 g heavier than the birds transferred permanently to 14 h.
3.	It is concluded that up to 6 temporary long days may be given (from 80 d of age) without affecting the timing of sexual maturity, but that the provision of 8 or more long days will accelerate sexual development, though not to the extent of a permanent transfer, in most birds within a flock. A regression analysis of the ages at which the first and last birds in the groups given 6, 8, 10 or 12 long days matured suggested that about 20 d of photostimulation are required to achieve a mean age at first egg similar to that of birds permanently transferred to long days.

Acknowledgements

We wish to acknowledge the dedicated devotion to duty of Frances Salisbury and Ann Kinsey in the running of this trial.