Oh and a horse will buck if they are barn sour or herd bound. But I think that's usually the only time they'll buck out of orneryness. The day she rode him here last week, she said she could tell he wasn't bad to be herd bound, I trotted ahead of her and she said he didn't seem to mind.
Becky
Horses that are broke might buck/hop a little if you are slapping them on the ass, particularly at a refusal, or if they are feeling good and you run them out.