The AQHA handbook mentions it very briefly:
"(1) Optional equipment...
...(E) Braiding of mane and/or tail in hunt style"
My horse has a very long mane, though, so I'm thinking that maybe I should braid it so it's not covering her neck. Here's a picture to show how long her mane is:
Would it be appropriate to do regular braids like that? Or a running braid, like this? Or should I just leave it down?