It makes me sad!
What do they do with them, Where do the old, hurt, lame ones go?
They can't find homes for all of them.
After the summer camps, where do they go?
We all know the answer.
I worked for a ranch that did backcountry guided trips in the West Elk Wilderness in Colorado. We did not have our own horses but leased then for the season from a place like this. At the end of the season, we returned them and the company kept them over the winter. These horses always came to us fat, sassy and well maintained. We took very good care of them during the season, or we would never see them again. Every year we would get a slightly different batch, as the horses were divided between us and other outfitters.
Suffice it to say we never had any serious injuries, so didn't have to deal with that. But, I suspect any injured horses would be dealt with no differently that yours would be.
One year we did have a couple who came down with strangles. We treated the whole herd and kept the ill ones apart, until healthy.
I'm not sure why you had such a negative visceral reaction, but those horses looked lovely and I would happily have taken any number of them. Fat and sassy.
This is a photo of the guides and owners of the outfitter. Do you see any thin, neglected or abused horses?