yep, this.
Brahmas can be frustrating cause they can be pretty slow to mature. Being familiar with a pea comb and how it develops is key here. also, on buff birds, the males will get darker shading on the wings, females won't.
These are all young cockerels. Two barred Rocks and a buff Brahma.
some type of game hen, maybe Old English? Definitely female.
Can't see the comb on this bird. I'm thinking a Delaware from the barring in the tail, or a mixed breed. Pullet, I think.
And the naked neck is a female.