The spikes on the legs, also known as spurs, take longer than 6 months to develop, so you first have to look at their combs, waddles and tail & back feathers to be able to tell if your chicken is a guy.
If your chickens are making weird "bawks" they could just be getting close to laying. If they are crowing, they could be a guy, or they could be a dominate hen, who is talking the role of a cock, if you don't have one.