They look like White Leghorns. It looks like you have some with more upright combs and some more floppy. My guess is that the upright-combed ones are boys and the floppy-combed ones are girls.
They do look like Leghorns, a full body shot would be better, but from what I can see, they do look it! Girls comb flop over right when they are getting ready to lay, the roosters stay straight up. How old are they? Have you gotten any eggs yet? If not, you should be very very soon!