I have a mare who is very cranky when other horses are sharing the arena. She turns out with other horses without any issue, is a very sweet horse on the ground and under saddle, but the moment a horse looks at her in the arena she gets so angry pinning her ears and showing her teeth. Other horses can be behind her, coming towards her, or on the other side of the arena and she will still try to focus her attention to the other horse and be complete mean girl about it.
How do you guys typically handle a situation like this and do horses typically “grow out” of it? I try to expose her to more arena traffic to get used to clinics, shows, etc but I’m not sure I see it getting better with more exposure? Any thoughts?