What does put hair on the Boy's chest mean in the great horn spoon?

In the novel "The Great Horn Spoon" by Sid Fleischman, the phrase "put hair on the boy's chest" is a colloquial expression meaning to toughen someone up or make them more resilient. In the context of the story, it suggests that the challenging and adventurous experiences the boy goes through will help him grow and mature. It implies that facing difficult situations head-on will help him develop strength and courage.