I understand. Your time would be longer, but your cost per pound would come down, that is my experience. You have to clean or move the tractors pens a lot if they are confined, or it will get more than nasty.
The confinement is the main issue for me. I'd love to just pasture them, but we have a lot of predators. This batch I had in a tractor which was in electric netting. I didn't lose any, fortunately.
That's one of the reasons I'm looking at trying to manage a dual purpose flock. Longer growth periods, smaller batches, and healthier. Like I said, though, I have no idea what I'm doing. I'm learning as I go. My expectations may be unrealistic.