The ramp might be your problem. My ducks never go into their coop at night until I go out and heard them in. But I just get them moving in the direction of the door and close it behind them. I can see how getting them all to climb up that ramp would be a challenge. I'd put walls around the bottom of the coop and let them make their home in there. You'll have an easier time getting them in a ground level door. Your run sounds predator proof enough that, personally, I wouldn't worry about locking them inside a physical building at night but that's just me. I don't know what kind of predators you've got in your neighborhood.