I have 5 silver-laced wyandotte chicks that are 14-15 weeks old. I can't tell if they are all roos or all pullets. When I purchased them, there were supposed to be at least 3 pullets and 1 roo. They threw one bird in for free, but they didn't tell me the gender of the free bird.
I think this one may be a roo... Here is a close up of its comb. It's the only one with a defined rose comb. All the rest have smooth rose combs as of yesterday.