I'm raising grey rangers (naturally) and gourmet black. The greys will finish at 81 days, the blacks 21 days later. I expect them all to finish around 5 lbs dressed, but will let you know more detail. In general, they are putting on weight nicely and are also extremely active. They're always trying to fly out of the tractor and stay quite busy scratching and foraging.
In the UK and Canada, part of being "organic" includes husbandry practices. Chickens for meat must be 81 days old prior to slaughter in order to be organic. Therefore, slower growing, broad breasted meat breeds are being developed. Because, can you imagine it, at 81 days your standard Cornish X would already be dead from a heart attack. I usually have 25% mortality on meat chickens, so finding these has been very rewarding.