I'm guessing your chicks were about a month old in these pics and I think the chick in the top pic is definitely a roo. Can't see the combs well enough to guess on the others.
They are 6 weeks old. I think the first two pics are the same bird.
But I'm not sure.
I have 2 in particular where the combs are starting to turn pink.
I have a 3rd who's upper beak, and nose has turned very dark, but not red or pink.