Hen or Rooster? Why You Can't Sex a Chick by Looking, and How DNA Sexing Works

Spring is the biggest hatching season here on the farm. The incubators are running full throttle, some of the hens are starting to get broody, and nearly every week brings a new batch of chicks. It also brings the question we're asked more than any other: "Is it a hen or a rooster?"

With most purebred breeds, the honest answer for the first few weeks (sometimes months) is that nobody can tell just by looking. Some breeders that specialise in just a few breeds have lots of experience in breeding them and know exactly what to look for, and can have higher success, but never 100% as a rule. That's why we don't take the risk and DNA sex every chick we hatch.

Why most purebred chicks are so hard to sex by eye

Day-old chicks of both sexes look almost identical with a majority of breeds. Combs, wattles, tail feathers and saddle feathers, the features that make a rooster obvious, only develop as the bird matures and you know what you're looking for. In some breeds you can make a confident guess at six to eight weeks. In others, Silkies being the classic example, plenty of experienced keepers have been caught out by a "hen" that started crowing at five or six months.

That matters for backyard chook keepers, because roosters are not allowed in residential areas under any local council laws as far as I know (check with your council for the rules where you live). I get a lot of phone calls about rehoming an unwanted rooster or two, and doing it successfully is not easy.

Common sexing methods compared

Vent sexing

Professional chick sexers can sex day-old chicks by examining the vent. It takes years of training and a lot of practice to do accurately, and it isn't something to try at home, as it's easy to injure a chick. These days, it is not at all easy to locate a chicken sexer, and even if you are able to, they can be very rusty from a lack of practice.

I've actually been reading a book on Australian chicken sexers given to me by the one and only Meg Miller, Editor of Australasian Poultry magazine, and it's fascinating. The Japanese were very good at chick sexing way back when it was a well-paying job. They could sex thousands a day with sometimes 99% accuracy. Alas, that is now in the distant past.

Feather sexing

In some chicks, the length of the wing feathers at hatch shows whether they are male or female. This only works when the parents have been specifically bred for it, which is mainly the case in commercial laying hybrids. For most purebred breeds, wing feathers tell you nothing reliable that you can use for sexing.

Sex-linked colour crosses

Crossing certain colours of rooster and hen produces chicks where the males and females hatch in different colours. It works well, but by definition the chicks are crossbreeds, not purebreds. This is how our Hy-Lines are sexed, with the boys hatching a darker golden colour and the girls a canary yellow colour.

Autosexing breeds

A small number of breeds, such as the Cream Legbar, were developed so the chicks can be sexed by their down colour and markings at hatch. Unfortunately, they are the exception rather than the rule.

Old wives' tales

Egg shape, swinging a ring over the egg, which chick is bossiest, whose comb is "a bit pinker", keeping fertile eggs in the fridge for the first few days, etc. All fun to talk about, but more about not letting facts get in the way of a good story.

How DNA sexing works

Birds have sex chromosomes just like we do, but the other way around. Hens carry two different sex chromosomes (called Z and W), while roosters carry two of the same (ZZ). A DNA test looks for the genetic markers that only hens have. If they are there, it's a girl. If not, it's a boy.

Here's how we do it at Talking Hens:

1. Every chick gets a numbered band so we can match each bird to its result.
2. We take a small blood sample from every chick in the hatch, labelled with its band number.
3. The samples go to a NATA-accredited DNA laboratory in Melbourne for testing.
4. Results come back matched to each band number, so we know the sex of every individual chick long before it would be obvious by eye.

It adds time and cost to every hatch, but it means that when you buy a chick or pullet from us, you are getting a female. No guesswork, and no surprise crowing at dawn. The only time it is wrong normally stems from "human error" on our side — not from the DNA lab. Of course, we will accept any bird back that turns out to be a rooster with a full refund or replacement bird. We've only had two roosters returned, ironically, from the same customer, out of the 1000s that have been DNA-sexed and are now happily living in suburban backyards.

Bringing new birds home

Whether your new birds come from us or somewhere else, a few basics make the move easier:

• Choose a breed that suits you. Think about temperament, size, how they handle heat and cold, and whether you want lots of eggs or a more exotic, colourful bird.
• Quarantine new arrivals for at least two weeks away from your existing flock. It's standard biosecurity advice, and especially worthwhile this year with H5 bird flu in wild birds.
• Buy from a known source where you can ask questions about the birds' age, health, history and of course, sex!
• Introduce them slowly. Let the flocks see each other through wire for a few days before mixing them and keep a close watch on them.

If you'd like to hear first when our next DNA sexed hatches are ready, make sure to sign up for our weekly newsletter near the bottom of any of our website pages.