Hello and welcome! From my experience, I have always had chickens, ducks, and guinea fowl together. Tho only problem I run into is water water water! Everywhere! Ducks need their water but they sure do make a mess of it. So far I haven't had any confrontations between all of them. As long as they have plenty of space they should do just fine. These guys are on half an acre to roam and they all go into the coop together at night.