Why do two or three-month-old puppies always chase chickens and ducks?

According to animal behavior, this behavior is an instinctive rejection of animals. Probably because of his master's preferential treatment, he mistakenly thought that all humanoid creatures were kind. With growth, this phenomenon will be alleviated, but ... chickens and ducks? Is your home near the agricultural product market? Still in the countryside? If so, try your best to do it well, and don't overdo it while disciplining, otherwise it will lose something irreparable: the confidence and fierceness needed to guard the door.