“The Mustang” is a Belgian-American drama about a Nevada prison rehab program where convicts tame wild horses for sale to the public. The film project was developed through the Sundance Institute, so founder Robert Redford is given producer credit. Matthias Schoenaerts (“Far from the Madding Crowd”) plays Roman, a convict who blooms when given the chance to work with the animals. Bruce Dern, Connie Britton and Jason Mitchell are among the supporting cast members. “The Mustang” marks the feature film debut of writer/director Laure de Clermont-Tonnerre’.