Who does Palmer find in his room the night before the pigeon shoot? Why? What do we learn about Palmer?

Beans, Mutto and Henry come into Palmer's room in the middle of the night, and the four boys sneak over to the railroad station where the pigeons are kept for the shoot. It is here that Palmer comes to realize how many five thousand birds really are. He runs away when Beans begins to rip open a cage to get to the birds. Palmer is struggling with his desire to be part of a group and a valued member of the gang and his aversion to the unkindness and cruelty the gang so often takes part in.