Depends... i know not much of a precise answer but it's an honest one. Technically, by providing an "area" that they know gives food, shelter they should return mine do.. we keep a 1/3 of an acre fenced and that contains the housing, all feed and pools and then i open the gate they can go where the please.. i do keep full flight here and my breed flys so the girls can fly out anytime, they return BUT you'll notice no river and no pond... that can be a huge enticement.
Most ducks will sleep on the water, i keep calls and they do... so a river would be a tough thing to pull them from, again a dedicated area where food is would likely help, but no guarantees.
Housing ducks and chickens, people do i am not one of those people lol ducks are messy and what they do to water is not what chickens want to play a part in, my standard hens free range so do go in the duck area it's a short live arrangement, they are rather indifferent to each other but i dislike how chicken peck, they could easily catch a ducks eye, plus their roosting could leave a duck rather icky. I again have a breed where they do roost so less risk of that but still... most ducks are on the floor.
As well, it must be said drakes will go after hens( meaning female chickens!) they are not compatible.. and can worse case kill a hen, now not all do.. i keep drakes here too, they don't bother my hens but they have ducks of their own and again are not housed together, it's a caution that must be mentioned however because of the the possible deadly outcome.