Chicken "trees " for roosting

Anyone tried a "tree "  with roof for roosting? Something like a tall coop without walls at the base.   I had some fox attacks this year and the ones that got away had jumped onto high roost points or on top of the fence. I did a little research on wild chicken population, and they are quite able to survive under bridges. Which got me thinking,  in an enclosed yard it seems that roost points shielded by a roof would keep the owls away at night and give a place to easily jump to during the day.  Wouldn't give protection to the nests, but id collect eggs daily and have a rooster or dog in the yard.  

My goal is to figure out a way to have chickens that can essentially run wild in a large fenced in area. Some shelter to keep them safe and warm, but without the need to let them out and put them up nightly.  Anyone heard of such a setup?

Interesting question.  I have a few birds who insist on sleeping outside.  I have a roofless version up.  It is designed to take a roof. I just got hung up on what kind of roof. My problem is that it has a basic design flaw. I designed it so it can be moved. My fear is that if I put a roof on it, it will fly in the first good gusts of wind.  I suppose sand bags on the legs would help.

So to answer your core question, I have had no vanishing chickens who have used it.