I have 2 Cayugas, and they usually sleep in the same coop with the chickens. Sometimes they lag behind, maybe still swimming in the pool, or finding "dusk" goodies, and miss the automatic door's deadline. In that case, they go sleep in the bottom, pen section of my A-Frame "tractor-type" coop.
They always sleep in the same spot in the chicken coop, so their night-time mess is easy to clean up. It's not all over the coop.
They get along well with the chickens, although their curiosity does startle a hen now and then. They bill EVERYTHING, and if a hen is in the middle of a dust bath when the ducks play with her feathers just then, it really ticks her off. *chuckle*
I have lots of waterers around, with one made out of an Alhambra bottle just for the ducks, so they can put their heads into it and under the water. The chickens drink out of it too, but they have nipple waterers available to them. (I have seen the ducks actually drinking from the nipple waterers now and then!)
I feed everybody on grower/finisher (general purpose) feed, and a couple time a week I'll add some powdered Brewer's Yeast to a special tin dish just for the ducks (when the chickens are elsewhere, or have gone into the coop for the night). ....and I offer oyster shell free choice from a tuna can nailed to the inside coop wall, for the laying hens.....
Plus, I bought a 300 gallon stock tank to use as a duck pool. ;-)