Sexing barnvelda chicks
Featured Stories on BackYard Chickens
You can tell by combs but not before they turn red. Sure a larger comb at this young age points to being cockerel but that's only one of many clues to telling sex from hatch to 5 weeks when cockerels will usually start showing color. Legs, stance, comb and by breed other identifiers are all used for sexing.
Take a Barred bird for example. The above is all true then you also have the shape and size of the white dot on head as a clue. Also the amount of dark wash color on legs is a clue. No one clue is accurate but with all of them together and experience to have a "feel" of it, sometimes it's an art, you become darn near 100% accurate in determining sex in first week. There are exceptions, some birds will fool you. There can be a large legged pullet that's mearly stout. Things like this will deceive and why a combination of all identifiers is used, mulled around in the mind to compare all and see which direction of sex they point to.
Other types of combs have specific identifiers like pea comb and looking at the ridges. Rose comb can not be determined by red color as pullets with rose combs show color early. And the list goes on...
Edited by Egghead_Jr - 5/9/16 at 3:19am