a roof, flooring, and sides all completely covered so nothing can chew, dig, climb or jump inside. ducks are good with routine so if you put them in the coop every single night they will learn to go in on their own
domestic ducks are domestic for a reason. they will NEED a predator proof house at night, a routine so they know when to come in, and daily feeding of waterfowl food to stay healthy, same with domestic geese
wild ducks are only wild if they are born in the wild, so no matter what you are not...