Either use an automatic door, or build a secure enough run that you don't need to close them in the coop.
You can also just accept the occasional lose from predators and never actually lock them up. Mine come and go as they please and are never locked in.
There are plenty of ways to keep chickens, you just need to figure out what works for you, and what you are comfortable with.
Theses are all good ideas. And the best point of all, what YOU are comfortable with!
@tereza911 it really depends on your environment. When I lived in the city in So Cal... never closed the door and never had a loss, not even an enclosed run. Cats don't worry me for full grown chickens. Now where I live, the predator load is much higher and I would be very uncomfortable doing that. My son lives in town, 2 miles from me... but they have tons of raccoon. Don't think I would even be able to free range there. They even hang out on peoples' porches.
Probably enjoying peoples' pet food.
Also when I lived in the city, I didn't collect my feed and had rat's visiting. Now I know there may be rats around, but they aren't getting a free ride to reproduce at my house and I collect my feed every night.
Just remember, if you do use treats... keep them limited so as to not upset the balanced nutrition. Since I ferment my feed the chickens think dry feed (pellets don't have too much dust for me) is a treat!
So when I toss that out, I know I'm not diminishing protein or other valuable nutrients. Of course they love live meal worms (or dried, slightly less nutrition). Summer time, frozen peas are a favorite with good nutrients. They love corn but I avoid it since it's more like a candy bar and that's what their feed mostly is anyways.
Pics are always welcome!