Don't get me wrong about other dual purpose birds. I keep two breeds. They can get fair weights by 14 weeks. 3.5 lbs dress weight is nice but the carcass of say Rock are long and lanky. It grows the skeleton then starts to fill it. Not as much meat nor as pretty of a carcass as Dele, NH or Buckeye which will flesh more in breast and be more compact. They'll have some breast meat compared to the ultra thin Rock breast at broiler age.