A chicken cannot escape at night. It cannot see. It is nearly blind at night. They just sit there and get picked off.
Further, daytime predators can come from the air or the ground. Are you telling me you have no eagles or hawks out there?
No Weasel, mink, skunks or raccoons?
Listen to beekissed on this. Lock your birds up at night, give them a place to hide during the day. If you want them for lawn decorations that get stolen over time, just let them run around and never protect them..
I have a ton of hiding places for mine and I still lose some.
The ONLY hawk attack I've had was under the cover my birds had gone to, and the victims were two of my roos {d'Uccle and silkie, but still. }