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R.K. Bramwell Extension Reproductive Physiologist

Introduction

Many backyard flock owners wonder: “When my baby chicks grow up, will they be boys or girls, roosters or hens, lay eggs to eat or crow endlessly in the early morning hours?” Regulations against owning roosters within city limits may exist in some of the larger cities. Not wanting to watch roosters fight and possibly injure each other in the hustle to establish dominance in their little world, or simply wanting to have a flock of only hens to gather the eggs each day for the family to eat. These are some points that cause concern and are important for the backyard chicken grower who tries to sex their chickens before they hatch, or grow up in this case.

“Old Wives Tales” about Sexing

Sexing baby chicks is not an easy process. There are a few who would try to simplify the matter with “old wives’ tales” of how to sex baby chicks. One method often repeated is tying a needle or a weight to the end of a piece of string (if the subject to be tested is an expectant mothers’ stomach, use a wedding ring on a string) and hold it over the young animal. One interpretation of this method says that if the object rotates in a clock-wise circle, it is a male; if it rotates counter-clock-wise, it is a female.

Similarly, with the same object on a string held over the baby chick, the motion of the hanging object in any circular pattern indicates a female while movement of the object back and forth indicates a male. Success of this method has been “reported” to be as high as “it will work every time” to “it works most of the time.” In actuality, one should expect to be accurate about 50% of the time when determining the sex of baby chicks in this manner (accuracy may be slightly higher for inherently lucky individuals).

A second method is to observe the shape of an egg to determine the sex of the potential young chick to be hatched. One individual explained that the different sexes require different shaped eggs for optimum growth within the shell and that the hen’s body knows which sex the chick would be. Football-shaped eggs house boy chicks, and more oval or round-shaped eggs will house girl chicks. He went on to say he was “nearly 100% accurate” when sexing chicks by this method. In actuality, the shell of the egg is formed simply by the presence of any object within the oviduct.

Years ago someone surgically placed an engagement ring in the upper portions of the oviduct and allowed the hen to form an egg (albumen and shell, no yolk) around the ring. The egg was then given to the girl in the form of a marriage proposal. The ring had no sex, but the shell was formed regardless. Similarly, a rock placed in the oviduct or more naturally sometimes detached body tissues in the oviduct can stimulate the formation of an egg by the hen. The accuracy of this method is about 50%, again, slightly higher for lucky individuals.

In a recent meeting it was mentioned that birds might be similar to reptiles in that the temperature in which the eggs are incubated largely determines the sex of the developing chick. Imagine if this were true, how valuable this would be to the poultry industry! Commercial egg producers could hatch only young pullets; chicken and turkey meat producers could hatch male chicks for one market and female chicks for a different market. Unfortunately, it is not quite that simple in domestic poultry. Too much deviation from the optimum incubation temperatures will most certainly result in fewer chicks hatched. Likely some of each sex will be lost.

Accurate Methods of Sexing

Fortunately, there are some methods for sexing baby chicks that are actually accurate. Using our knowledge of genetics with the proper breeding scheme, day old baby chicks can be sexed based upon their color. This is possible when using what is called sex-linked color traits. Mating barred hens (black and white striped feathers) with non-barred males results in barred males and nonbarred female chicks. This can also be accomplished using birds carrying specific genes for silver and gold color patterns in the roosters and hens (silver males bred with gold females results in silver pullets and gold cockerels). From a genetic standpoint (excluding mutations), this method is always accurate.

Vent sexing baby chicks is a method popularized in the 1930s by a Japanese professor, Kiyoshi Masui. Individuals well trained at chick sexing schools can consistently and easily attain greater than 95% accuracy. This method involves holding the day old chick upside down in one hand and while visually examining the vent area for the presence or absence of a rudimentary male sex organ.

This method sounds much easier than it really is. After being taught the basics of this technique from non-professionals, most people would be doing well to obtain 60-70% accuracy at best. However, if interested, additional written information on this technique can be obtained from the Center of Excellence for Poultry Science at the University of Arkansas. Most commercial hatcheries that offer chicks for sale as either pullets or cockerels utilize this method.

All in all, the best way to sex chickens in the backyard flock is to watch them grow. Feed them, water them, observe them and enjoy them while they mature. As they develop, changes will become obvious as the males will begin to act manly and their voices will change from the chirping common to young chicks to attempted crows. In nearly all breeds of chickens (Sebrights being the exception) the young males’ feathers will also change from the round oval-shaped feathers common to hens and young birds to the shiny, more narrow and pointed feathers found on their necks and at the base of their tails.

Additionally, the combs of the young roosters will begin to develop at an earlier age than they will in females. While this may vary from breed to breed and, in some breeds, might even be difficult to detect a difference; in most breeds of chickens with large combs, this is a very obvious distinction between young roosters and hens as they are maturing. In short, enjoy the birds and watch them grow. This is definitely the most enjoyable method when establishing a backyard flock.

Summary

While a number of “old wives tales” exist about sexing chicks, these methods are no better than flipping a coin. While feather sexing and vent sexing are accurate methods of determining the sex of chicks, perhaps the best and most enjoyable method is just watching the birds grow.