If she has a pea comb, at 10 weeks, you would see 3 deffinate rows. Having said that, I had 2 pea comb birds that I just gave away that I could not determine sex on at 11 weeks. Not all birds follow the rules.
Penny has got me stumped, BUT roos do make all the same sounds that a hen does, he just has his own different variety of noises on top of the normal chicken noises....
I'm 100% sure this is a hen. i have 2 exactly like her. She's a banty that explains the tail feathers. More specifically she is a Miller Fluer d'uccle. I'm going to be showing mine next spring. I'll try to send a pic of my rooster.