They can't be left alone in an unsecured coop at night, or you could lose them all. During the day they can fend for themselves, but you may still lose a few to predators.
If you know the type of predator you are facing, do as much counter measure as you can. Get your own dogs, lots of human...
It's fun letting them free range, but it is double the stress. Every night when I sit in my coop waiting for them to come home is stressful and time consuming. And the anxiety of when they don't come home at night never goes away. I do nightly headcounts and talk to them. That feeling when there...