anxious horse - what am I missing?

I agree with this, also suspect the pig may have something to do with things. Even if the pig is gone, his smells remain.

May sound stupid, but I have a gelding that is TERRIFIED of pigs. I went riding at a friend’s house, her adult pig got loose. I had to pull the horse trailer down the road a significant distance in order to get my horse calm enough to load. The pig is long dead, but the smells/memory remains. Every time the horse has been back to that property, he watched for that dang pig.

An old outfitter told me pigs smell like bears, and his horses hated the smell. He also said he used to butcher his hogs and try to desensitize the horses to the carcasses (smells) to get them ready for hunting so they were able to use the horses to pack out game, including bears. not sure how true the pig/bear correlation really is, but after watching my horse absolutely lose it when he was approached by a 600# hog, it sort of makes sense.

Or maybe my horse is just 1/2 chicken…

Although, I have seriously considered finding a pig to borrow (or even raising one) just to desensitize my horses.

I didn’t read through all the posts…but I will say that I have a mare that is highly sensitive to MSM. It makes her anxious and jumping out of her skin nervous. Last year I was about ready to give up, as she was so hot (not mean just like she was on high alert at all times…sneezing or touching her made her jump). I tried many things…as a last ditch effort, I read some things about MSM affecting some horses, so I figured it wouldn’t hurt to try taking her off the joint supplement (which had high MSM levels). In a few days she was quieter…in 2-3 weeks she was down about 10 levels. Now, she is always a hot and sensitive mare…but at least now she is not ready to explode in her own skin.

That said…I also had a mare that had a melt down when I was a kid and took her to 4H Fair and she could hear the pigs.