Meg Donnelly and Drake Rodger have been cast as the leads in “The Winchesters,” the CW pilot that acts as a prequel to the hit series “Supernatural.” Donnelly and Rodger will lead the series Mary Campbell and John Winchester, respectively, the parents of “Supernatural’s” protagonists Sam (Jared Padalecki) and Dean (Jensen Ackles) Winchester. Mary is 19 years old and has been fighting the forces of darkness since she was a child. After losing someone close to her, the hardened hunter considers qu