My 6 yo appendix has always been a little crazy but in the last 2 months she's become completely psychotic, she rears and has flipped over with a surcingle and side reins on. She is not lame, probably could use a floating, doesn't seem to have any back problems or be sore anywhere.
As a 4 yo she recieved 4 months of dressage training and she was doing well. About a year ago she injured her left rear fetlock somehow and chipped off a piece of bone. It opened up again after about 3 months of healing and then healed up again. I've had no problems out of that and the vet says she's fine and she's by no means lame.
About 2 months ago she started tossing her head if you asked her to do something she didn't want to do. Then I went to ask this new lady at the barn if she wanted to try her on some barrels. When I got on to show her to the lady and asked for her head or tried to turn her she started rearing up, I was mortified! So I got out her surcingle and side reins and as sson as I started walking her she yanked her head up and freaked, reared up and flipped over backwards, broke my side reins and nearly cracked her skull on a wheelbarrow and a fence (luckily just missed), I'm really glad I wasn't on her.
Anyway, I've now tried a halter and a hackamore and neither one makes a difference. She does it if you're on her or off and no matter whats on her head. It seems to be a disrepect thing and she does it to anyone. I'm at a complete loss on what to do. I've owned her since the day she was born and I've invested a lot in her. She's so sporatic and random that I can't catch her with a water balloon which is what a lot of people have suggested. And to top it all off, I'm pregnant and can't be on her when she's like this, so I can't 'win' because if I get on and she starts to go up I have to bail. I don't know what to do and if I can't fix it soon she's gonna have to go and I really don't want that to happen. She's so talented and so smart and really a nice horse when she's loose and you're on the ground. She's even great if I hop on in her stall.... what do I do?