I concur with the others who suspect you have cockerels in your brood. Lack of comb size and spurs at this age is no indication of them not being boys, but an early attempt at crowing is a big clue.
Examine the comb buds on the top of the heads of all of your youngsters. Compare. Are there any that appear more red than the others? Those are the ones who are likely trying to crow and are cockerels. Also, if these are a breed that produces multi-colored rooster feathers, if you part the feathers on the back and examine the pin feathers emerging under that outer layer, you may see some very bright colors not present in the other pullets.
Examine the comb buds on the top of the heads of all of your youngsters. Compare. Are there any that appear more red than the others? Those are the ones who are likely trying to crow and are cockerels. Also, if these are a breed that produces multi-colored rooster feathers, if you part the feathers on the back and examine the pin feathers emerging under that outer layer, you may see some very bright colors not present in the other pullets.

