I've had Pointers (same type of dog as Weims and Viszlas), both field lines and show lines, excellent hunters, ZERO interest in my waterfowl or chickens. They're supposed to have a soft mouth. In fact, I took my 5 month old Pointer pup to an intro to hunt tests group last weekend. He got his very own quail to do whatever he wanted with (wing feathers plucked). Boy, did he love that! He chased it, caught it, carried it around, but DID NOT KILL IT. They aren't bred to kill. They are supposed to point out the bird, then retrieve it after it's shot. Not catch it and eat it themselves. What good is a hunting dog that eats your birds????
It might be how I raise my dogs, but I've never had any problems with my hunting dogs. They know the difference between a game bird and domestic poultry.