My friends, who have had chickens for 2-3 years, free ranged them, with only a rare one gone missing due to predators. We got 4 of their older ones for a "trial run", as they needed space for new arrivals. So I built a small coop, and free ranged them. One of the main reasons I wanted them around is to eat the overabundance of bugs.
They had a lot of attacks recently, and have removed 2 foxes and a raccoon. I removed the fox we had. Haven't seen anything else threatening.
I'll be making a run for when we aren't around, etc. Maybe one of the moveable fence things too.