It depends on the breed of dog and the environment in which the dog lives!
Some dogs have hound genes, and sometimes they show hunting behavior. A friend of mine has a yard in the countryside, and has more than 2 chickens. At the beginning of the week, dogs and chickens were peaceful. On that day, my friend went to a party, went out in the morning, and came back at noon to see the chicken carcasses in a yard. Only three chickens were afraid to come down, while his dog was staring at them with a mouthful.
Later, I asked a friend who is engaged in animal research, and he said that this may be an atavism phenomenon, because these chickens and dogs will not eat them, just as prey, for their owners!
Of course, this is just one kind, and there are also dogs that will eat chickens and ducks.
Most dogs don't have the above two situations. They are all successful domesticated offspring, and they are docile and friendly to people and animals!