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To help sell the film to theatre exhibitors and the public, the Paramount press department featured a number of contests to get the word out about the newest The Marx Brothers laugh fest. In addition to "Name the Four Marx Sisters," there was also a proposed duck-hunting contest, in which hunters across the fruited plain would bring back their catch to be cooked in one big duck dinner, beginning with duck soup, of course. And then there was the duck parade. Just imagine, to paraphrase the Paramount press materials, after you round up four ducks (preferably from a poultry market or a farmer), dress them as the Brothers, and let them lead the parade, you, the faithful theater manager, could then create more nonstop hilarity by tying the ducks together with a long string. "The ducks will not stay in line but that will only add to the confusion and the excitement," the press materials helpfully added.
Italian dictator Benito Mussolini banned the film from Italy because he thought it was a direct attack on him. When news of this reached The Marx Brothers, they were reportedly ecstatic.
Screenwriters Harry Ruby and Bert Kalmar were standing on the set one day when an extra standing next to them said, "I don't know who wrote this stuff but they ought to be arrested...they should be in a different business." Kalmer, who was known as a rational and calm man, said to Ruby, "I'm going over to hit him. Who does he think he is? He's just an extra!" But before fisticuffs erupted, Kalmer and Ruby were informed that Chico Marx had paid the extra to rib the screenwriters, just for the hell of it.
Shortly before this film premiered, the city of Fredonia, New York, complained about the use of its name with an additional "e". The Marx Brothers' response was, "Change the name of your town, it's hurting our picture."
Final film of Zeppo Marx. After the film's premiere, he quit The Marx Brothers, citing a dissatisfaction with movie acting overall, and a weariness with being the butt of jokes regarding him as the "unfunny" Marx brother.
Groucho Marx offered the following explanation for the movie's title: "Take two turkeys, one goose, four cabbages, but no duck, and mix them together. After one taste, you'll duck soup the rest of your life."