We live in VT also and our first hatch was similar sized. We let the next group of 19 go out to 12 weeks and they dressed out between 7 and 10 pounds with huge breasts. We feed Broiler food 20% from the time we get them until 2 weeks before hatching then switch them to a 24% finisher to help them round out and put on a few extra pounds. It seemed to work because these birds were monsters.