When I raise CX, I use an 8x8 brooder for the first three weeks. I use an 8x8 chicken tractor that get's moved daily (twice per day near the end) for 35 days. I can house 40 birds in the tractor. I feed them an 18% protein broiler feed from end to end. My goal is for the birds to dress on average at 6lbs at 8 weeks. Plan your freezer space accordingly.