A horse rescue north of me just bought out an entire truck of horses headed for slaughter. 26 total. They didn't say where they came from, but from the few seconds you can see each horse come off the trailer, they look fairly healthy.
There's another kill pen outfit just south of me, and they will pull out the better horses and put them up on Facebook for a week to 10 days with a price. You can't PPE them, or even ride them, you put up the money, come to pick them up, and at that time you can decline the horse if it's worse off than their video showed. Lately they've had several horses with Yellowstone brands on their hips, someone asked where they were from, and the page just said "google it". I haven't been able to find anything online whether they're left over from the show, or if there's a ranch by that name that sold off their stock, or what happened.