The peacock that most people are familiar with is only one half of the peafowl family. The other half is the peahen -- the name for the female peafowl. Identifying the gender of juvenile peachicks is known as "sexing" the chicks. According to Feathersite.com, sexing peachicks is very difficult to do accurately without the use of a lab or blood test. However, there are some signs that you can look for to identify the differences between the sexes while the peachicks are still young. You should be able to separate most of the chicks by the time they are two months old.
Hold the chicks in your left hand. Turn the chicks over so their bellies are exposed. Look at the chick's vent below the tail. This is the area where future sex organs will develop in the peachick. If the vent has a small protrusion or bump, the peachick is male. If the vent is a smooth area, the peachick is female.
Allow the peachicks to grow for two months. Male peacocks will have longer legs than the females. If you measure the legs at approximately two months of age, the males should have slightly longer legs. You can then separate the hens from the cocks with some accuracy.
Wait a few more months for primary feathers to start to develop. If you have the standard blue and brown peafowl, you should be able to determine the difference in sexes between nine months and one year. The males will develop dark, chocolate brown primary feathers. The female will develop more muted brown, greyish primary feathers.
Listen and watch the chicks as they develop. The male chicks may show higher signs of aggression.
Consider having a blood test down on the chicks. This is the only way to tell fore sure what the sexes of the chicks are in the first year. While you can made educated guesses, it is impossible to know with finality. If you have to know the sex of each of the chicks, such as for business and sale reasons, a blood test is a worthwhile investment.