Have you seen any of them crowing? They all look like hens to me (based on their age)
my RIR hen that lays me a daily egg, looks exactly like ALL your pics... and my rooster has more green feathers on his butt (he's half RIR and half Cochin, so he has a fluffy butt and feet though.) but his comb is 3-4x the size of my female.
I was worried I got all males with the RIR because our hen developed a comb too - but all the other Roo's I had, their combs just kept growing, while her's stayed small, like the ones in your picture.
If they aren't crowing and are old enough to start laying eggs, you'll know soon enough though.