How do you actually tell if a silkie is a roo?

[Rainbowninja]

Do they just take much longer? I've been looking at pics online, but I swear they look so similar!!

 

[Holdthechicken]

I think it’s agreed they are one of the most difficult breeds to sex before they either crow or lay an egg. But if you have a closeup of the comb and wattle line at like 8+ weeks and above people on here can give guesses!