I have a very temperamental OTTB mare. As long as there's no face to face contact she doesn't mind horses being near her while she's not being ridden. But as soon as she has a rider she pins her ears at every horse that gets near her. It always happens at the trot and canter and about half the time at the walk. I have no clue why she's like this.
I thought it might be a pain issue. I check her back before and after every ride and there's never been a problem. Her saddle isn't a 100% perfect fit but it's not to narrow and doesn't rub her withers. And she doesn't show any signs of pain when she's ridden by herself.
I also thought it might be something that happened to her in her racing days. Maybe she learned to associate the sting of the whip with a horse approaching from the rear. I have no idea.
So far she's only kicked at one horse (she missed). But she always pins her ears and slows down. I don't know what to do other than to keep her moving forward when she slows down so the other horse doesn't get within kicking range. How can I correct this? I ride in group lessons all the time and plan on showing her this summer. If she keeps this up she may not miss the next time she kicks.