Here are two types of gender sexing that farmers and hatcheries generally use on baby chicks today: vent sexing and feather sexing. While sexing most chicken breeds with 100% accuracy is still impossible on a large scale, there are a few methods of sexing baby chicks that at least provide correct gender selection between 95-97%.
What does this mean?
For starters, it means that when you order 100 pullets from your favorite hatchery, your chances of actually getting 100 pullets is … about 0%. It also means that you should adjust your expectations when ordering from a hatchery or picking up sexed day-old pullets from your local farm supply.
Vent sexing is a method of sexing day old baby chicks performed by carefully inspecting the baby chick for male genitalia. Vent sexing is incredibly difficult because unlike many other animals, the location of the sexual organs are inside the bird and difficult to identify to the untrained eye. Vent sexing can only be performed safely and accurately by a trained professional, and if done improperly can cause serious injury or even death to the chick.
Vent sexing is time consuming, and the lack of professionals trained at this obscure and difficult trade make it difficult for many smaller scale hatcheries to keep up with the demand. So while vent sexing is usually around 95% accurate when performed by an expert, finding more than a few in a small farming town is a tall order. Expecting them to accurately sex thousands of chicks on a hatch day before sending them off to their new homes is a “whole ‘nother” story. You’re probably going to see vent sexing accuracy closer to 90% when ordering from a hatchery that offers vent sexing.
Thankfully, there is an alternative that is utilized by many hatcheries in addition to vent sexing to alleviate the burden of vent sexing thousands of cockerels and pullets during the busy hatching season.
Feather sexing is an ingenious method of chick sexing that can be learned and practiced a bit easier than vent sexing. That’s not to say that it isn’t vulnerable to human error as well. However, if done properly the offspring of selected breeders can be sexed by feather characteristics (covert and primary feather length) with about 80-95% accuracy, depending on the breed.
So if it’s easier, why not feather sex all chicken breeds?
Well, it doesn’t take a mathematician to see that 80-95% accuracy isn’t quite as high as the 95-97% you can achieve by properly vent sexing. However, because it’s safer, faster, and easier to teach, it must be utilized in order to offer gender sexing on so many of America’s favorite chicken breeds. Another reason why feather sexing isn’t used for more breeds is because it’s a bit tricky to properly breed the chicks so that they actually exhibit the feather characteristics necessary to sex the birds on the first days after hatch.
Without going too deep into the genetic specifics, by selectively breeding chickens with the slow and fast feathering sex-linked genes K and k, male offspring will have coverts that are longer than the primary feathers for the first few days. On the contrary the female chicks will have shorter covert feathers than primary feathers. That means that these chicks can only be sexed accurately using this method for a few days. If the breeding is not done exactly right, this method will fail to produce offspring that exhibit these feather characteristics.
So how can I be sure I only receive pullets?
If you’re truly looking for 100% accurate sexing, you have limited options. You can either purchase older birds that have already begun exhibiting traits that identify them as pullets or cockerels, or you can purchase what is called a sex link chicken breed – a breed that can be gender sexed based solely on chick coloration on the day of hatch. Some breeds are naturally sex-links, like the Barred Plymouth Rock. Others are created by crossing a Male and Female of two specific breeds that will produce a hardy and productive cross with a clear color differentiation between pullets and cockerels. One of the most popular sex-link varieties is the Gold Sex Link, also known as the Golden Comet or Cinnamon Queen. This Gold Sex-Link is created by crossing a Rhode Island White Hen with a Rhode Island Red Rooster. What do you get? A hardy bunch of yellowish white cockerels and reddish buff pullets!
Egg producing farms that order baby chicks once or twice a year to keep a continual supply of young healthy egg layers, they will often choose a sex-link production variety like the ISA Brown so they can be sure they won’t end up raising any males.