I'd say the one to the left in the pic (mostly white fro) a pullet and the one on the right (with black in fro) a roo. Just a guess. I looked up a pic in my catalog. How old are they? Are they hatchery stock?
I have hatched way too many chicks to remember how old they all are, lol. My thoughts were that the more white crested one was a hen and the other was a roo too but I haven't had houdan before and they don't develop the same as the Polish I have had. No they aren't hatchery stock. They came from someone here, though I can't seem to remember who right at this moment.
Can you pick them up and move the ends of the wings a little to expose the saddle feather area? You might be able to see some development of the saddle feathers. That would be a giveaway to identify a rooster.