We raised our own 3 years ago, a 40 pounder. We had to buy a scale so we could figure out how long to cook him. My DW decided it would take too long to cook whole, so she had me cut the legs and back off. The breast on the bone alone still weighed 20 pounds, but a more manageable a size, so we cooked one leg with the breast. I’m not sure how long it took, but we just used the thermometer. Best bird we ever ate.