Stephine, I think you could make the design work by making it a slide to the left/right door.
The coop my DH made used a ramp with hinges, putting the ramp up to close the door and using a hook and eye to keep it closed. They don't need a ramp if they aren't going and out.
What DH did was to make a ramp, add hinges, and when we wanted to close the door (like twice in ten years), we just lifted the ramp up and used a hook and eye to hold it there.