I'm so proud of Nova, I almost started crying during today's session. I tried operant counter-conditioning, and she took to it like a champ. After just 15 minutes, she voluntarily stepped into the water, letting it touch her hooves (and then she immediately stepped back after getting her treat lol - baby steps).
Her legs are good enough now that I'll pause the mite treatment and focus solely on wash stall training. The mites will return, but it's a risk I'm willing to take if it means she'll become comfortable enough that I can wash her without crossing her threshold of fear.
We also trained target-following in the pasture afterwards, and she did amazing! I was able to stand at her outside shoulder and walk her in a volte!!! It wasn't a perfect volte by any means, but just the fact that I can turn her away from me while still keeping her attention on me is huge. She's such a smart cookie :')
I've also concluded that the sores at the front of her hocks are sallenders, and I will manage them accordingly. Wish me luck TvT
Edit: Oh, also, Nova almost spooked twice today because a shovel got tangled in her tail and a tractor drove too close. Both times I used that 'woah' cue we've been practicing, then gave her 10-15 seconds to process the situation, and it worked perfectly. I'm so so proud of her.