I have ducks and chickens, and just about everything else running free range around here, for the ducks and geese I have a proper drinker on legs which they love, the chickens use this too, then there are eltex drinkers dotted about the place, don't have a problem with the chickens going in the pond but I don't have duck feed floating in it. I round the ducks up on a night and they go in their seperate house and the chickens go to roost in their own houses, sometimes they share, my philosophy is so long as they are locked away from predators and are happy then they can go where they want. I feed them all twice a day and the ducks, geese and hens are getting enough feeding as well as what they get from free ranging. The drinker on legs holds 30 litres and is a good investment especially in this hot weather, might be worth a try.