Effect of rate of stimulation on hatching time in Japanese quail

A series of Japanese quail clutches was incubated, then one egg from each clutch was stimulated at a rate between 1 click/10 sec. and 1000 clicks/sec. The hatching time of the stimulated egg was recorded and compared with that of its siblings. Embryos stimulated by discrete clicks at rates of 1 1/2–60/sec. were speeded up; while those stimulated between rates of 100–500 clicks/sec. were slowed down. These results are considered as contributing towards a possible explanation of the synchronisation of hatching in this species.