“The Hand That Feeds” is a new documentary that follows the attempt of a group of New York fast food employees to form a union to get better wages and working conditions. It will be shown in Chicago on Tuesday, March 10, at 7:30 pm as a part of the new “Docs at the Box” series at the Music Box Theatre, 3733 N. Southport Ave. Following the screening, filmmakers Robin Blotnick and Rachel Lears will join a post-show discussion.