For a while, my Cayuga pair slept in the chicken coop, but after a while, they declined to go into the coop by the time the auto door closed. I left the A-frame coop open (nobody slept in there) for them to go into, and they did for a while, but when I closed it at night they got unhappy. So I left it open after that... and they stopped going in there to sleep. Now they patrol the whole yard, front and back, and even wander over to the land-lady's house during the night. They have NEVER used the duck house I built especially for them, either. But they range with the chickens just fine. I have a kiddie pool for them (from which all the poultry drink) in the back yard and trough in the front yard, too. They have plenty of places with deep water to dunk their heads, as well as to splash all over. They just don't sleep inside any structure.
Now I have four call ducks, and they don't like their duck house, either. They sleep UNDER it.
But the chickens and ducks get along just fine.