one way to identify the gender of chickens ( once they are feathered) is to look at the combs, lobes and the 'rump' feathers. If they are pointy/ taper to a point then its likely / definitely likely to be a boy. if the feathers are softly rounded then its a girl. the problem with differing breeds is that some have very different wattles and combs so they aren't a reliable source unless you know a lot about that particular breed. However in saying that, from the comb of this polish I would say that its a girl ( and its lack of wattles also suggest this) however the tail feathers aren't very clear. Could you post a pic of the ' rump' to tail feathers?