Hmm. I see why you suspect some males.
At age 16 weeks, some of those red combs might be pullets getting ready to start laying.
At 12 weeks, they're more likely to be males.
I'm pretty sure I see at least one male (all red, white feet, no other chickens in the photo.) In addition to his red comb & wattles, he appears to have male-specific saddle feathers (skinny, pointy feathers growing just in front of the tail, that will hang down on both sides as they get longer), and he's got darker red patches on his wings (more common on males than females.)
The red bird with a black tail and yellowish legs and a scraggly tail also looks male to me, for the same reasons (picture after the other one I mentioned, with a gray chicken behind him and some other ones in the background too.)
The last two photos (3 birds total) all look female to me.
For the other ones, I'm not sure but maybe someone else with better eyes will be able to tell. That gray one particularly has me puzzled: I'm seeing the big comb and wattles, but the feathers are looking female to me right now. But 12-16 weeks is right around the age that pointy male saddle feathers start to grow, so the bird might be a male that hasn't grown them yet, or might be a female that never will grow them.
Other people may be able to spot details that I missed, or things might become clearer over the next few weeks.
(And of course if you do find one crowing, you know about that one!)
