CASPER, Wyo. — A campaign sign for Republican gubernatorial candidate Megan Degenfelder was found zip-tied to the fence of Powder River Prep on Thursday — a potential violation of federal law. Oil City News received a tip from a reader early Thursday afternoon that the sign was hung at the nonprofit school in violation of U.S. tax law. Two staff members visited the 500 S. Jefferson St. site and confirmed the sign’s presence between 2:30 and 3:15…