Autosexing breeds

An autosexing breed is one in which the chicks at hatching can be sexed by their down colouring. It was when crossing the gold Campine with the barred Rock in 1929 that Professor R. C. Punnett and Mr M. S. Pease discovered the basic principle in their experimental work at Cambridge, and made the Cambar.

Barring is sex - linked, there being a double dose in the male and a single dose in the female, the barring being indicated by the light patch on the head of the chick. This light patch is very similar in chicks of both sexes having black down, but when the barring is transferred to a brown down there is a marked difference. The light Head - spot on the female chick (one dose) is small and defined, while on the male chick (double dose) it spreads over the body. For that reason, the down colouring in the day - old cockerel is much paler, and the pattern of markings more blurred, than in the newly hatched pullet chick, which has the sharper pattern of markings.

Standards which have been passed by the Poultry Club are gold and silver Brussbar; Brockbar; gold, silver and cream Legbar; gold and silver Cambar; gold and silver Dorbar; Rhodebar; silver Welbar; Wybar. The cream Legbar, Legbar, Rhodebar, Welbar and Wybar standards are given below and all other standards for autosexing breeds are held by the Rare Poultry Society.