This is a no-brainer. The Ducks represent Americans, and the Hens represent the Jews. Rockwell even manages to include lies told about the Geese, who represent the Germans. He also covers the formation of Israel represented by the Swans who are the Palestinians.
This poem was written in 1952 and is eerily prophetic. Was Rockwell a psychic, or merely astute? He tried to warn us, but we didn’t listen.