What does Beizi's bench leg mean?

Bench structure. Beizi bird's bench leg means that the male Beizi bird's chin has a structure similar to the bench leg, showing a convex shape, similar to the bench leg. In the breeding of Beizi bird, the bench leg is considered to have certain influence on the quality of Beizi bird, and Beizi bird known as "eight characters" or "big bench" is considered to be a better bird.