Broilers: confinement vs. pasture

How old are the cornish X when you guys are butchering? It seems to me that they're going to be pretty confined the first 3-4 weeks anyways, probably lots longer in winter, under the heat lamp until they feather out. We were thinking that if we butcher at 8 weeks, we're only talking about another few weeks past that, whether it's on pasture/range or in confinement. And in the winter, it seems like they wouldn't get much time at all outside anyways. I do love the idea of happy, natural chickens, and I can't imagine not letting my laying hens run around, but if we're talking strictly food production, and such a short time period anyways, I'm not sure that it really makes such a huge difference in their little lives. Maybe I'm just too practical or callous?

I always process my CX around 10-11 weeks. I let them free-range and I really don't push the feed, so it takes them a little longer. I like them big.

About 10 weeks here, too, when I had them on pasture with the others. I normally slaughter my broilers between 4 & 6 lbs.