I have 3 chickens that I am unsure of. I am 95% sure the bantam is a roo but the other two I am hoping are hens but it's not looking good. We already have a bantam roo that will be staying, he is my sons chicken. I started with 11 babies and I know for sure 2 are roos as they have crowed. The other 3 have been silent so far. The barred has the "cocky" attitude but the buff is calm and silent and not pushy at all. So I hope they are girls.
It's variable with different breeds because of different rates of maturity. But IMHO, at that young, with that much comb/redness, the chances are high that they are boys. Definitely think the buff is a boy with those wattles. Sorry.