It's comb is flat, I guess pea comb? I don't see any little bumps. Its is about 1/4 of the size of the barred rocks. What Bantam breeds come barred with pea combs?
There is, essentially, a bantam breed for every large fowl breed. There are some exceptions (OMG I WOULD DIE FOR A LF SILKIE) but there's bantam counterparts for most.
The most popular bantam breed with barred pattern is the barred cochin. But this one, obviously, has clean legs. Cochins don't. To make it even more confusing, I recently discovered that bantams CAN breed with large fowl birds! I don't quite know how they manage to reach/not get squished, but whatever. It's happening in my own back yard, and I'm hatching out the eggs to prove it.
So it could be darn near anything. You're probably looking at a mixed breed either way.
I will say though, that it looks like a hen to me. The comb is still very yellow to be a rooster.
I'm guessing that it is some sort of mixed breed bantam, maybe with one of its parents being a Dominique. Must have the frizzled gene somewhere, too. Looks to be a pullet to me.