Still scared of other horses in the arena

Worked on general things this week like straightness, turns, the six buttons. Not in the planning was a couple of one rein stops. Aslan gets very reactive if another horse in the arena gets too close or he thinks they are riding up behind him too fast. One horse was being backed quickly and she turned her butt toward him (about 8 feet away) and started hustling backwards. Aslan had a heart attack and spun around, so I KEPT him in a one rein stop and moving around and then made him do several leg yields in both directions until he softened instead of leaning on that bit.

The other time was just a family of people riding and one horse was cantering and coming up behind him and he just felt very uncomfortable and worried about the other horses. My little scrapper is a bit of a coward lol

It did take me a long time to just get him to be not so nervous with other horses in the arena in general. Someone jumping really upset him. Now he only gets upset if they knock the jump loudly. But the more I think about it, the more I think that just loud unexpected sounds give him the willies. Not surprising for a prey animal, but still, that needs to be addressed. I plan to go to the Mane Event in April, which is a large horse show/trade show. There are clinics and demos, all done in front of an audience. The applause is going to freak him out, not to mention a moving audience full of colours.