When can I tell if she's a he?

[s6bee]

Has anyone ordered from Meyer Hatchery in OH.? Did the extra chick turn out to be a roo? I'm counting on that happening but I'm not convinced yet.
I have 4 week old chicks and of course they threw in an extra one. I've been trying to identify the breed they gave me but I don't care as much about that as I do if it's a HE!
There is NO sign of a comb or waddles at 4wks.2 days old. Is smaller in sz. compared to my Deleware, and Austrolorp and BR. Looked like a Silver laced Wyandotte as a chick but a bit darker but is turning mostly black w/ a few specks of white. I am not good about posting pics. so if someone can guide me I'd appreciate it so I can do so.
In general, when should I know if I have a Roo?

Thanks guys

 

[silkiechicken]

There is a sticky somewhere on how to post pics... as for when to pick out if it is a roo. 6-8 weeks is a good time if you have comparisons. If it's comb starts to pinken and redden earlier than the rest... you may have a roo. Girls's combs wont turn red till about 4 months old, rather than 2 months old for roos'.