LPM 221: Commercial Poultry Production and Hatchery Management (1+1)

AUTOSEXING

• When sex-linked genes produce characteristics in newly hatched chicks that are readily recognizable, these characters can be used for sex identification.
• The Rhode Island red x barred Plymouth Rock cross is a good example of this.
• The barred Plymouth Rock females carry the gene causing barring.
• The female chicks resulting from the cross of a non-barred male and a barred female would not be barred, since they would not receive the B gene from their mother, while the male chicks would be barred due to the dominance of the B gene received from the female.
• The down of the newly hatched chicks does not show barring, but those that will later develop barred feathers have a white spot on the back of the head. Thus the males will have the white spot on the head and the females will not.
• They can be sorted easily at hatching and this method is known as Autosexing.
• Another sex-linked gene affects rate of feathering in chicks, and it can be used in the same manner.
• Leghorns and some other breeds are characteristically rapid feathering, whereas most of the American and other heavy breeds are slow feathering.
• Slow feathering is dominant to rapid feathering, and if the cross is to be used for sex identification it is necessary to mate rapid-feathering males with slow-feathering females; chicks from such a cross show well-developed primaries and secondaries which not only extend well beyond the down, but which are also longer than the associated wing coverts.
• In the slow-feathering male chicks, by contrast, the primaries are much shorter, are of about the same length as the coverts, and the secondaries are either absent or poorly developed.