They sure are pretty! I can't answer your question because I'm new to this whole chicken world, but I have a question for you. How quickly did your cochins feather in? Were any of them slower than the rest? I ask because I posted a picture of my 4-week old cochin (not bantam) and everyone has told me it's probably a rooster If you look in my profile, check out my pictures and you can see the chicken in question. It's a partridge cochin; it's feathering in so slowwwwwly.
2 and 3 are pullets i want to lean towards cockerel on 1 but at that age mine had bigger wattles and a bigger comb that was much much more red you can see them in my albums.