The ability to tell the sex a baby chicken is not an easy process to learn and takes training and experience. The importance of knowing the sex of the baby chicken saves the manufacturer of these poultry products from raising chickens until they are old enough to distinguish the male from the female. It takes four to six weeks for the chicken's secondary sex characteristics, such as the size and shape of the roosters comb, to become noticeable enough to tell the between the two sexes.
Cloacal, or vent sexing is the oldest process that is used today to tell the between day old hens and roosters. The process involves examining the baby chicken's vent, located underneath its tail, looking for a genital organ. If the sex organ is can be seen in the vent, it will look like a small pimple and the chicken is a male.
The feather method used by breeding a fast-feathering chicken with a slow-feathering chicken. The sex of the baby chicken can be determined during the first 48 hours. The female will have longer primary feathers with the secondary feathers shorter. The male's wing feathers will be of the same length.
The sex link method, which began in 1975 by commercial breeders, is breeding to produce a distinguishing color between the two sexes of chickens. Red Star chickens have a very common sex link: the females hatch out reddish gold and the males hatch out a yellowy butter color. Black Star chickens hatch out black for both sexes, but the male has a white spot on the head.
The best method to determine the sex of a baby chicken is to watch and wait until the chicken gets old enough to be able to distinguish between the two sexes by their size and most importantly, their very prominent markings.