I have one turkey about 12 weeks old that was hatched with several chicken chicks. The turkey, the adult hens, one adult rooster, 14 twelve week old chickens, and some 4 week old chicks that the broody has already weaned all free range from sun-up to sundown and are locked in a coop at night. They all eat Grower and I have oyster shell on the side for the laying hens, though they eat very little of it.
The turkey, a midget white, is not growing as fast as he would if he were being fed strickly a higher protein feed, but he does free range practically all day every day and eats very little of the commercial feed. He is a good forager. He is only 12 weeks old, so I am not sure how this will turn out, but the turkey hangs with the chicklens for the most part and roosts with them at night. I have not seen any problems, though I wish I had a second turkey to keep him company.
I don't have ducks so I cannot comment on them.