Well, after spending several months observing my own Indian Runner Ducks in all the different sorts of weather we get in Tennessee, I've noticed that the ducks tend to rest during the day in different areas of the edible landscape depending on what sort of weather we're having. 

If it's hot and summer, they might rest in the shade so they don't bake in the 100 degree heat. If it's warm but not blazing, they have taken naps in the sweet potato patch planted beside the duck pond on a hill. When it rains, they have their day time naps in a thick patch of some sort of ground cover weed that popped up on its own. 

By taking note of all these different resting spots, you can see that the ducks still aim to be warm and dry whenever they can as they certainly have the option to nap on bare clay ground, which they almost never do. 

So how can we use that information to improve the duck house and reduce the amount of labor needed to keep a duck coop clean and liveable for our water birds? We can add plants that continually suck up the moisture left behind from duck excrement and the vigorous dunking of duck heads in the watering bucket to keep the duck coop floor drier. As those plants' roots spread and continue to grow, overlapping atop each other, they add more cushion and "new bedding" to the duck coop, with no additional work. 

The duck coop is a place for the most durable of plants as ducks are very... insistent about pulling up plants. 

Let's talk more on that. 

You're looking for something fast-growing, shade tolerant, evergreen, perhaps cold-hardy if you live in a climate that has cold winters, something that either grows close to the ground or is easy to keep trimmed, or... the ducks find delicious, so they'll keep it trimmed themselves. 

The more vigorous the plant, the better able it will be to resist the nonsense of ducks. 

Similar criteria as the "planted floor" list. We're looking for plants that are evergreen, will possibly grow in and out through chicken wire, for those using chicken wire, will tolerate the cold if necessary. It certainly wouldn't hurt if they are also edible for the ducks to give them additional greenery at night.