Waterfowl coops ought to be designed so you can herd them into a dead-end where there is no option but to go in the door. Every night I lean a piece of siding against the sliding door opening (closed to where there's only room for the duck/goose to go in. And the other end against the fence parallel to the door--so they're kind of running up against this temporary "wall". They can go in or try to get past me. They're terrified of me 

, so they go in.
They're temporarily using a tool shed that the chickens (who are very good about going in) used to use. When I build for them, I am for sure gonna consider ease of herding!