Whiting True Blues: What age should I be able to tell roosters from pullets?

[HuskerChickMom]

I have some 3 week old Whiting True Blue chicks and I was wondering at what age they will start showing gender differences. I am new to this breed, but LOVE all the different colors I received so I'm kind of hoping there's at least one male in with the girls. If I don't have a male, I'd like to order one ASAP which is why I am wondering how soon I will know the sex. I should have ordered one the first time around, but figured I'd probably get one in the order, right now they all look the same to me.

 

[nuthatched]

Probably around 6-8 weeks, like anything goes else (except silkies)