OP, two things jump out at me:
It’s just been my experience, which is not to say all race tracks are this way, but I haven’t seen many hot-shoeing farriers in my neck of the woods at the track. They all, as far as I know, cold-set. The horses are re-shod quite frequently - more frequent than most sport schedules.
It very well may have been your mare’s first time and a hot-shoe is a very shocking thing for first timers; I don’t blame horses for being fearful of it. I have seen horses move their leg for whatever reason (a fly, disobedience, whatever) and get positively branded by the shoe and then permanently associate the farrier with pain… For me, it isn’t worth it.
As we know, it only takes one bad experience for a mare to say “never again”.
I’m betting she was surprised by the noise/smell/sensation (which horses recognize innately is BAD - they’re burning!) and when she was punished thereafter, came to the conclusion that she wanted no part in any future endeavors with that person.
I would switch farriers definitely, and I would look for other options besides hot-shoeing.
Additionally, it has never been my experience that making a horse circle/move around when they’re fearful has worked. I have never witness it work for someone else either. When they’re scared I don’t think treating them like they’re being disobedient is the right way to go. You want to teach them to stand still when they’re scared, not dance around at the end of the shank like a kite in a thunderstorm.
I propose that this problem is two, nay, threefold:
- She needs to learn to stand quietly for the farrier.
- You need a farrier that does not evoke a fear response in her.
- She’s young and from what I read, on restrictive rest - she needs a J O B
- I know I said there was three, but she needs a good experience with a farrier.
So, my suggestion is to work on having her stand as you bring objects to her feet, pick them out, etc. Don’t punish her for moving back or being afraid. Calmly re-position and retry.
Then, when it is time for her farrier visit, dorm or torb her. I think she needs to have a few good experiences even if it is cold-set. Get a new farrier and tell the farrier no hot shoeing for this mare.
I have never seen a good outcome, for horse, farrier, or client, when one part of the party despises or looks down upon the other part. The farrier has a chip on his shoulder, your mare has a chip on her shoulder, you probably have a chip on your shoulder – time to move onto better things. 