our birds have 24 hour access to outside. They have 24 hour access to an inside coop and an enclosed run also.
They are outside from before the sun comes up until after it gets dark. They come back to the coop every night. I have NEVER lost a chicken to a preditor yet. Age, Natural causes, things like that yes, but never has one been attacked or killed by another animal.
there coop gets closed up at night, but there is a window they could go out if wanted. They how ever don't do that.
They eat all the bugs, grass and weeds they want. I give them treats daily (breads, cerals, fruits, veggies). They also have feed, scratch, grain, layer, oyster shells, etc. etc. available 24 hours a day. During the nice (no snow) months they don't really eat to much as they are outside getting all the food they need. During the winter months the food amount goes up quite a bit. Mine don't seem to like to be out in the snow.
I have a boundry fence in the front yard (running along the road). And then we have pastures fenced off. Other than that there are no other boundry fences here. We have 40+ acres, but the birds stick pretty close to the barn and house. They do go into the pasture and forage, but for the most part they stick close to home....
Our ducks, geese, guineas, chickens all run together. No problems or fighting.