I am updating this thread, our Black Australorp (Sprout), despite showing initial signs of being a cockerel, has laid her first egg at 22 weeks! She also has a massive comb which is probably why her comb was red and large after only 6 weeks
I've never been more confused by a chicken (9 weeks today). She/he developed wattles and a comb pretty early on, around 3/4 weeks. I was pretty sure this was a cockerel (as did many others). The comb and wattle color and sizes in the pictures below have been basically the same since the 6.5 week...