Join Date: Dec 2012
Location: North West England
• Horses: 0
Horses are herd animals, and as a result she feels uneasy being alone. There's safety in numbers, and she's now alone with just you, a predator, on her back. You could perhaps do some ground work with her to help her trust you a bit more? Walking over plastic bags, and grids in hand are both going to bombproof her and convince her to trust you at the same time.
My mare used to do this a lot, I'd catch her in from the field (Where her herd are) and then take her out on a ride on her own, and she would call out to them. I just told her to move on, and did ground work with her, and it rarely happens now.
The herd instinct is exactly that, and instinct, and you'll never completely abolish it, but by improving your relationship with your horse and perseverance, you'll start to see improvement.