The way my bird supplier put it, free ranging means accepting there's going to be some predator losses.
I've got a very nice chicken tractor that's completely predator proof, plenty big for my 13 birds, and I pull it once a week giving them fresh grass. I could use it strictly as tractor (what it's designed for), and my birds would never be exposed to predators, and perhaps a day could come that predator pressure forced me to use it as it's intended.
As superior as a tractor is because it constantly provides fresh ground and grass to them within it, at this point, I still free range every single day, all day.
I have this very expensive structure that's being used as little more than a heavily fortified field coop right now.
But I'll also say, it's a lovely feeling being able to let them enjoy their free ranging, and at the same time know they're absolutely safe at night, and if if it's necessary, I can confine them in comfort.
I don't think we can overestimate the additional benefits of free ranging. I'm getting 8 to 10 eggs a day consistently out of 12 hens in the dead of winter. I think it's the free ranging, and quality feed.
On the chicken happiness scale which oddly enough means a great deal to me, there's great joy in providing another creature with a happy life.
I love looking out the window seeing how much they're enjoying themselves and how happy they are, they follow me around and seem very appreciative.
I'll accept the risk of losses, doing what I can to to prevent them, but things would really have to change in regard to predators, for me to even consider confining them back to the tractor.
My glorified, and fortified, Flying Fortress Chicken Tractor!