I have an Americana that it's tail had the feathers pecked off. It never showed me either way on being a hen or rooster, until recently. The last couple of weeks, I caught it being overly aggressive with the "other" hens. Then I heard a "new" rooster crowing. I started to pay closer attention to the pen, looking for this new rooster. Well, I caught him, it was my aggressive Americana "hen". The aggressive nature he was displaying was his attempts to mate with a hen. Now, I have a rooster I thought was was a bit long legged for an Americana and looked more like a Russian Orloft, but I accepted it as an Americana rooster: especially since I bought it at the same time I got the other Americanas. Where is this going, other than me sharing? If it walks like a duck, quacks like a duck, it's a duck, right? What I see right away in your pic of your rooster (yeah, I said rooster), is that he has curved tail feathers, not strait like a hen would. If he is being aggressive with the others, then to me, that would seal the deal sexing it as a roo.