The red ones look like pullets, if they are red sexlinks then they are definitely pullets. The silkie is a clear cockerel. And I usually can't tell with silkies.
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I agree with @junebuggena the red birds are pretty pullets and the silkie is a handsome cockerel. But silkies are very hard to sex and at this age, there is no guarantee until he either crows or lays an egg
Ditto but, in this case I do think it is a silkie cockerel, he is non bearded and showing a lot of wattles at this age. If you can make generalizations about silkies at all - hard because they are so difficult to sex early) the girls usually have a narrow comb and the boys a wider one - they are called "walnut " combs and that's what males generally have. The only truly UGHLY part of a silkie, I always think they look like tumors.
This particular chick is somewhat narrow in the comb but, has lots of time to broaden.