One of the most difficult tasks for the backyard chicken breeder is that of sexing young chicks.

Modern commercial hatcheries use a variety of tricks that allow them to determine the sex of every chick from the moment it hatches. The most common way they do this, involves the cross breeding of birds of particular colours which result in male chicks having different colour down than female chicks. This is known as sex-linked crossing. I shall explain some of the more common sex-linked crosses in this article as well as give some pointers on sexing pure breed chicks.

Basically there are five different methods of determining sex in day old colour-crossed chicks.

The first of these is the common gold to silver cross. Mating a gold male such as Rhode Island Red, Buff Rock, Buff Leghorn, Buff Orpington, Red or Buff Sussex to hens which are silver, such as Light Sussex, Light Brahma or pure White Wyandotte, results in all the cockerel (male) chicks having whitish grey or pale brown down, whereas the pullets (females) have reddish-brown or buff down.

The second cross using the hens mentioned above with black red type males like Old English or Modern Game, Welsummer, Brown Leghorn, Dark Cornish or Barnevelders gives very similar results, except the female chicks have brown stripes and markings. The male chicks have a lighter greyish colour with black and grey markings.

The third cross involves non-barred males such as Australorp, Black Leghorn, Rhode Island Red or Ancona mated with barred females such as Plymouth Rocks or Cuckoo Leghorns. The resulting chicks are all black or dark brown with varying degrees of white underneath, however whereas the females have dark brown or black heads, the males all carry a whitish spot on the back of their heads.

The fourth mating relies on leg colour to determine the sex of the chicks, but as leg colour is not always clearly defined in day old chicks, it is not as reliable as the above methods. Mating dark legged males such as Silkies, Minorcas or Campines to females with light shanks such as Sussex, Leghorns or Wyandottes gives male chicks with pale legs and female chicks with dark legs.

The last of these five methods uses feathering as a guide. Mating an early-feathering male such as an Ancona or Leghorn to hens of a slow-feathering breed like Sussex or Rhode Island Reds will result in male chicks which have very short flight feathers which do not protrude past the downy wing coverts and females which show definite wing flights which show clearly past the wing coverts. This method requires inspection immediately after hatching, before the males feather growth "catches up" to that of some late hatching pullets.

Of course, all these methods are completely useless to the serious breeder of pure breeds of chickens. In these cases, it takes a little longer to determine the males from the pullets, particularly with heavy breeds. It is usually a simple matter to pick light breed males at about a month old. They sport much larger and brighter head furnishings and are usually far more precocious than their sisters. With heavy breeds it is sometimes easy to determine the pullets by their faster and more even rate of feathering. Males feather more slowly and in a more patchy manner (but this is not always the case with some strains).

The best method therefore, is by observing the chicks' behaviour. Startle the chicks by sailing a hat or similar soft object over their heads and watch their reactions. The cockerels will instinctively stand erect with their heads upright and will emit a peculiar warning chirruping sound. The pullets will tend to crouch down low and remain silent.

The table below shows the most common differences in development between the sexes of heavy breed chicks at 5 week of age.