Chicken sexing

Chick sexing is the method of distinguishing the sex of chicken and other hatchlings, usually by a trained person called a chick sexer or chicken sexer. Chicken sexing is practiced mostly by large commercial hatcheries to separate female chicks or "pullets" (destined to lay eggs for commercial sale) from the males or "cockerels" (most of which are killed within days of hatching because they are irrelevant to egg production). The females and a limited number of males kept for meat production are then put on different feeding programs appropriate for their commercial roles.

Different segments of the poultry industry sex chickens for various reasons. In farms that produce eggs, males are unwanted; for meat production, separate male and female lines for breeding are maintained to produce the hybrid birds that are sold for the table, and chicks of the wrong sex in either line are unwanted. Chicks of an unwanted sex are killed almost immediately to reduce costs to the breeder.

Several methods are used to determine the sex of a day-old chicks. Some are effective only with certain breeds or crosses, while others are universal. The two chief methods of sexing chicks are feather sexing and vent sexing.

Vent sexing, also known simply as venting, involves squeezing the feces out of the chick, which opens up the chick's anal vent (called a cloaca) slightly, allowing the chicken sexer to see if the chick has a small "bump", which would indicate that the chick is a male. Some females also have bumps, though they are rarely as large as those of male chicks.

The eminence or genital organ is found midway on the lower rim of the vent, and looks like a very small pimple. Most males have a relatively prominent eminence, most females have none. However, a small proportion of both males and female have relatively small eminences. Sexing these chickens can be quite difficult, but with regular practice, the sexer will eventually learn to identify the differences.

When learning to sex chickens, it is best to assume that chickens with small eminences are female. The male eminence is solid and will not disappear upon gentle rubbing with one's thumb.

A paper about vent sexing was published in Japan in 1933 by Professors Masui and Hashimoto, which was soon translated into English under the title sexing baby chicks. After their discovery, interested poultry breeders hired those who had been trained in Masui and Hashimoto's technique, or sent representatives to Japan to learn it.

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