Originally Posted by Lobelia Overhill
Give her a chance! She's only 4 y/o and you've not had her very long... She's been taken from her home and moved somewhere else that has new smells, sights and sounds and different people. It's a lot for her to take in.
You need to take things slowly with her, spend time with her just petting
That would be accurate if you've only had her for a few days but you've had her for months and you rode her before.
There are two areas that I would be looking at if I were to come to work with your horse (since you had a vet check, I would have already ruled out teeth, etc).
The first would be the handler. Is the handler, you in this case, experienced enough to be dealing with a young, probably green, horse? Does the handler exhibit the alfa horse dominance necessary so that the horse knows who is in charge?
The second thing I would look for is fit of tack. Does your saddle fit your horse or is it making him sore? What is it about the tack that concerns the horse? Is the rider tightening up the cinch too tight at first? Is the saddle pad clean so that it isn't irritating him?
I recently took a horse in trade that was labeled "dangerous" by two trainers and broke the arm of the owner's son when he tried to mount. I took the horse to a friend of mine and she discovered two knots on the horse's back and that the 9 year old still had his wolf teeth. She took care of both problems, worked with the horse at the end of a 9' lead line for ~20 min, flexed him then rode him off with no problem at all.
You need to look at the factors I suggested and have someone more knowledgeable look things over and watch you handle the horse. Keep in mind that a 4 year old horse is like a toddler and will try to get away with as much as it can to test it's boundaries.