Brahma; what am I looking for to sex?

[SMan]

I'll refrain from posting more pics for a week or 3, but as they grow what am I looking to sex them? They are fairly young, but getting big fast.

My original pics are at https://www.backyardchickens.com/forum/viewtopic.php?id=194627 but they are a little young. Thanks for the input on the pics from anyone who did, for my knowledge though what am I looking for?

 

[Birdgirl]

usually you can look at the comb if its bigger and redder then its pry a roo.