Do they have any protection from predators or at least things they can scurry under if a hawk or something else comes along?

If they know where their roost is, and return to it at dusk, I would say you can let them free-range, then lock the coop at night so it is secure.

I let them range after about five months, they seem pretty dumb until then. Learned that the hard way! If you bought grown hens, let the stay cooped up at least two weeks, they know where the bedtime roost is by then. Best of luck with them, I love having my flock wander all over the farm, very cute sight.

Cheri