Yes Virginia, There is a Quintessential Thanksgiving Song
There are only a few Thanksgiving themed songs. Most people, including radio stations, begin playing Christmas music on Thanksgiving Day.
Yes, Adam Sandler of Saturday Night Live fame, released The Thanksgiving Song which has experienced some notoriety. But there is a long-running cult favorite that was born out of the 1960s anti Viet Nam protests that has become somewhat of a tradition to play, especially by Rock radio stations around the country.