I got a few 9 month old NH pullets bred by Jeremy Woeppel (GNH x Good shepherd hens) that are a tad over 7 lbs. I had the scales out for some birds I am taking to the Tucson show this weekend. I need to have my partner weigh the cockerel...Of course, he's decidely bigger.
Definitely mature fast...I actually have one pullet coming out of a full on molt at 9 months. She has not produced eggs during the molt...but the rest are laying very well (5/week) in November even.