I agree with cynthia, sometimes you can tell early by the comb. Even if its not actually raising yet, I find that sometimes the width can give it away. Most my babies still have tiny thin combs, and those are the ones ive always felt were girls. I got one however that was fluffier and larger then the others with a broader chest and I always felt it was likely to be a boy, and 2 weeks later im already noticing the comb on this one is getting wider then the others, which means im probably right lol. I heard you can also sometimes tell by the fluffing on the head. If it sweeps back or has streamers as they call them (pieces that are longer then the others and sweeping back), then its a boy, and if its round and fluffy its a girl. And also the hens are said to walk lower and more collected and the boys seem to walk taller and be braver. Not sure how accurate any of this is though. Then there's the typical wing sexing trick that works on alot of chicken breeds but that method is still questionable when it comes to silkies.