Soundtrack
Breaking with their usual pattern, neither Harpo's harp nor Chico's piano is used in the film, although Harpo briefly pretends to play harp on the strings of a piano, strumming chords in accompaniment to a music box that is playing the unlikely chime tune, "Who's Afraid of the Big Bad Wolf?" from rival studio Disney's Three Little Pigs, released the same year as Duck Soup.
The musical introduction to Groucho's character is similar to the ones in Animal Crackers and Horse Feathers but it did not become closely associated with him as did "Hooray for Captain Spaulding" from Animal Crackers.
Zeppo, as usual, plays, according to James Agee, "a peerlessly cheesy improvement on the traditional straight man", in his final on-screen appearance with the Brothers. He sings with the group (including soloing the first few lines of the first song, "When the Clock on the Wall Strikes 10"). He also sings with the others in "Freedonia's Going to War", filling out the four-cornered symmetry as the Brothers sing and dance in pairs during the number.
Read more about this topic: Duck Soup (1933 film)