My horse recently came back from being on trial. She was at her new home for 2 weeks, and came back because the woman didn't like the way she trotted (she has some trotting blood in her but doesn't pace). I hacked her out the other day and she was fine for about half a mile, then she just stopped dead. I was stuck there in the middle of the road for a quarter of an hour before I could get her to move. Even when I turned her for home she was backing, side stepping and giving little rears. I got off her and she was a perfect lady and walked away happy out, as we neared home I got back on her, where she proceeded to side step home :/ I am hoping to sell her, but I can't sell her acting the way she is, she has NEVER done anything like this before !! When she left our yard she was a nice mare, now she just seems defiant and bitter. I'm at a loss as to what to do, any help would be greatly appreciated.