The Swon Brothers hit number 6 on Billboard with new album
Duos have not fared very well on NBC’s The Voice. The one exception: The Swon Brothers, country-singing brothers Zach and Colton from Muskogee, Okla., who placed third back in Season 4. And they’ve continued their success after the show. Their debut single, “Later On,” reached number 13 on Billboard’s country airplay chart and number 21…