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Feather sexing is easy, but it requires that the chickens be specially bred to manifest their sex in differences in the feathers as hatchlings. These are usually hybrids rather than true breeds, and are called sex linked chickens. Female chickens in these breeds have longer wing pinfeathers than the males do, which makes them relatively easy to tell apart. Most chickens do not have these traits bred into them, and the hatchlings are identical to all but the skilled eye of the professional chicken sexer.
This method used to determine the sex of newly hatched chicks is only possible if a female from a slow-feathering breed is crossed with a male from a fast-feathering breed. The sex of the chicks produced from this cross can be determined during the first 48 hours after hatching by looking at the primary and secondary feathers located on the chick's wings. The primary feathers will be noticeably longer than the secondary feathers on a female chick. On a male, the primary and secondary feathers are the same length.