George Strait, left, and Merle Haggard perform at ACM Presents an All-Star Salute to the Troops on Monday, April 7, 2014, in Las Vegas. (Chris Pizzello/Invision/AP)
Merle Haggard performs in concert at Harrah's Resort in Atlantic City, N.J. on May 3, 2014. At 77, he still tours around the country about two weeks. (Owen Sweeney/Invision/AP, File)
Merle Haggard performs at the Atlanta Symphony Hall on Friday, Jan. 23, 2015, in Atlanta. (Robb D. Cohen/Invision/AP)
