Mine free range our farm and are such a joy to have running around and following me everywhere that I too wouldn't have the heart to keep them confined. We do, however, have two great dogs that stay outside and keep all predators off our property. Rex, our GSD, has recently started chasing the hawks that fly over. It's pretty funny cause while he's looking up and running and barking and chasing a flying hawk like a lunatic, he nearly runs into barns, stables, fences, etc.
Amazing thing is that when the hawks are circling overhead, I look around and wouldn't know I had chickens. There's not a one to be found. As soon as the hawk flys off, here they all come from under bushes and buildings - seems they just morph right into the ground and suddenly just morph right back where they were.
There's so much joy to watching them be chickens that I now couldn't/wouldn't do it any other way. Even our baby chicks free-range. We've never lost a chick and never had an illness or fighting issue - just lots of healthy, happy chickens that somehow know how to survive without our keeping them locked up.
But I would say that having dogs that guard your property and interact with and guard your flock is the key thing in free ranging.