What is the beauty of Yang Gongzi's answer?

This is the key part of the story. When Junping Kong saw Yangmei and thought of the child's surname, he deliberately teased the child: "This is the fruit of your family." It means that your surname is Yang and your name is Yangmei. You are family! This simple joke is humorous and interesting. The child replied, "I haven't heard that peacock is your bird." Where is the clever answer? Junping Kong made a fuss about surnames, and so did the children. The peacock thought of "Kong" surname: The best thing is that he didn't directly say "Peacock is a master of poultry" stiffly, but took a negative way, saying "Peacock is not a master of poultry" and answered tactfully, which not only showed due courtesy, but also expressed the meaning of "Since Peacock is not your bird, Myrica rubra is my fruit", leaving Junping Kong speechless. Because he wants to admit that the peacock is his bird, what he said is tenable. Andy showed the manners that children should have. His tone is euphemistic, witty, humorous and quick-thinking, and he also expresses that "Peacock is not the bird of the host family, how can Yangmei be the fruit of the Yang family", which makes him speechless.

I haven't heard that peacocks are Kongfu poultry. I have never heard that peacock is your bird.