Abstract

1. Oviposition patterns in dwarf and normal pullets were compared after the dw gene had been introduced into a White Leghorn and an Australorp strain, which had been selected for reduced oviposition interval.

2. The dw gene increased oviposition interval by about 2 h and reduced clutch length by two‐thirds in both strains. It also decreased the occurrence of intervals shorter than 21 h and of membranous and soft‐shelled eggs in the White Leghorn strain, but had little effect on these traits in the Australorp. About two‐thirds of the 17% difference in rate of lay between dwarf and normal pullets could be attributed to the difference in oviposition interval.

3. It is suggested that the dw gene may be useful in overcoming certain physiological barriers when selecting for shorter oviposition interval.