Sexing day-old chicks (University of Kentucky)
Sexing day-old chicks typically requires training. There are some "old wives' tales" on how to sex baby chicks but they are no more accurate than flipping a coin.
- A method that has been cited for sexing chicks before they hatch. It involves observing the shape of the egg. According to this method, football-shaped eggs will yield male chicks while more oval or round-shaped eggs females. In reality, the shape of the egg is not related to the sex of the offspring. In fact, a hen will produce a shell for any object passsing down the reproductive track and may or may not include a yolk. Similarly, eggs have shells whether or not the egg is actually fertilized or not.
- One method is based on the method used by some to determine whether a pregnant women is carrying a body or a girl. In the case of chicks it involves tying a needle or weight to the end of a piece of string and hold it over the chick. If the string moves in a circular pattern it indicates the chick is a female (pullet) while if the object moves back and forth it is a male (cockerel).
There are two 'accurate' ways to sex day-old chicks and hatcheries may use either or both of them depending on what breeds they are hatching out. These are vent-sexing, which can be used for any breed and sex-linked characteristics which are very breed-specific.
The reproductive organs of male chickens are located within the body cavity making it difficult to determine sex based on physical attributes. Male chicks have a rudimentary sex organ that can be detected by trained sexers. It is not easy though, as shown in the images to the left.
Source: Sexing day-old chicks: A case study and expert systems analysis of a difficult perceptual-learning task (Journal of Experimental Psychology 1987, Volume 13, Number 4, pages 640-645)
There are some characteristics that are genetically linked to the sex/gender of the chick. Sex-linked crosses take advantage of these characteristics to produce offspring that can be easily identified as male or female at day of hatch.