National Geographic : 1927 Apr
F Parents s Male: Barred Rock Female: Blaek Langshan First Generation. All of offspring are barred Second Generation All cocks are barred; one-half of hens are barred ; one-half of hens are blaek Parents Male: BlackLangshan Female: Barred Rock First Generation AIlcocks arebarred; allhens areblack One-half of One-half of Second Generation eocksare barred andone-half areblack; hens are barred andonehalf areblack THIS ILLUSTRATION OF SEX-LINKED INHERITANCE SHOWS THE CURIOUS RESULTS THATALWAYS OCCUR INCERTAIN CROSSES It will be observed that in the mating on the left the barred cock has transmitted his barred character toallhisdaughters, sons and grandsons, and to one-half of his granddaughters, whereas the black hen has transmitted her color to none of her sons, daughters, orgrandsons, and toonly one-half of her granddaughters; but in the mating on the right all the pullets of the first generation are black and allthecocks arebarred. The breeder, who knows the mode of inheritance of certain color factors, can mate his birds in such a manner as to distinguish thesexofhischicks assoon asthey are hatched. This recognition, if he desires to raise pullets for laying, enables him to kill the cockerels atonce, which saves him theexpense offeeding and caring for them until their sex is revealed by feather development (see, also, page 399).