Well if it is a rooster my 2 Japanese roo's are very confused, because they chase it all day long trying to mate with it, lol. I hope it is a hen, but either way I am going to sell it. I have way too many chickens, I worry how that happened, lol.
Well I was going to say hen as it just looks like one even though the comb and wattles are large, you say this bird is about 6 months? that's crowing or about to lay age for most though the comb is not as bright red as I would expect a roos to be at this stage and he should be crowing around now?? I know the hens can take longer in getting started with laying though...confusing this one as the feathers being frizzle doesn't make it easy!
but I can see why others say it's a roo due to the iridescence and long curvy tail feathers, though I have had black hens with a green sheen in their feathers too... incidentally what is the response of this bird to the mounting behaviour from your bantams? any crouching going on?