A barn dance?? This is the first I have ever heard that word used in reference to a barn dance.

In California & I imagine anywhere in U.S.A. a hootenanny was a gathering of folk singers in an informal setting, a coffeehouse, small folk venue, etc where several different folk singers were performing, sometimes known folk singers other times unknown singers.

Matter fact, many folk LPs from the early & mid 60's had the title of the LP "Hootenanny" with just a gathering of different singers with guitars & banjos. I still have a few of these LP's somewhere.
:-))