Since it’s April Fool’s Day and Joan Crawford’s birthday was last week… From September 1934: Clarence Brown pulled a gag on Joan Crawford that worked to perfection. In a scene for “Chained” Joan was supposed to shoot off a double-barreled shotgun. When Joan was scared practically to a state of paralysis, Clark Gable volunteered to show her all the tricks. Finally Joan got to the point where she could pull the trigger without flinching. The scene started and Joan picked up the gun, pulled it over her shoulder and fired. There was a moment’s silence and then from somewhere up above, an old stuffed duck fell at her feet. Brown…