Yep. Pressure from people against slaughtering horses caused the closure of the US slaughterhouses, precisely because the USDA removed funding for the inspectors. The other problem with slaughtering horses is that the head catch used for cattle often does not work on horses due to their longer necks, and as a horse moves his head, the captive bolt misses, and he's still alive when he's hoisted up and bled out. In order to have humane horse slaughter, you need specialized equipment and workers, which no slaughterhouse wants to pay for-- they want to be able to do horses on Monday morning and cattle Monday afternoon.
150 years ago, every community, even the small ones, had a knacker, butcher, or abbatoir who slaughtered horses. They were usually led in, grain dumped in feeder, and the horse was shot in the head or pole-axed. Meat was sold cheaply at the butchers, sold as dog food, ground and given to prisons, schools, hospitals, etc. Hides made robes, mittens, and furniture. Hooves and bones were boiled for gelatin and glue. It wasn't usually viewed negatively-- there were a lot of horses, and working families could not afford to keep animals that were too old or lame to be useful. Being 'sent down the lane' was the chosen end for the vast majority of horses, and nobody saw much wrong with it. Yes, it was unpleasant to think of the steady parade of horses dying there, but what else could you do with them? The alternative was leaving them to rot in the streets or mound up in ditches and fields. It was a necessary service, and most butchers, while not soft-hearted, were quick and experienced and the animals in their charge met a swift end. That's the type of slaughter we need in this country-- not the mass commercial slaughterhouses with equipment not meant for horses. The problem is that too many people don't realize that death comes for us all, and that the end of a 1000-pound animal is not pretty, but we are so far removed from the land and from real life, most people assume all horses can be fed and housed until they die peacefully of old age. Well guess what. Most horses don't die peacefully if left to their own devices. They starve to death and suffer greatly their last months. Starving is excruciatingly painful. If they happen to have enough teeth to chew, perhaps their legs ache and hooves hurt and they stand on arthritic knees and foundered hooves for years with no relief because they can still get around and get just enough to eat and drink to stay alive. They die of anemia bitten by thousands of ticks. They get trapped in mud, break their legs, or go down and are eaten piecemeal by scavengers when not all the way expired even in the absence of large predators. They die in agony over a course of days trying to birth a hiplocked foal. The creek dries up and they dehydrate.... an old or injured horse left to his own devices dies alone and in pain and stressed and it takes a very long time to die. Most old horses do not just lie down and peacefully go to sleep. Anyone with a clue knows that, but the general public does not. A quick end is the best most horses can look forward to at the end of their lives, and that's just the way it is. A rifle at the butcher or a quick injection at the vet is a kindness. A 2-hour trip to a US slaughterhouse that is inspected with trained workers or local butcher to be turned into dog meat is preferably to a 2-day trip across the border to a Mexican slaughterhouse with no regulation. But our culture is so afraid of death, we want to close our eyes to the fact that it's a needed service that we don't want to think about or see, and in return the animals suffer.
"Doing what's right by the mustangs" may in fact be a quick, low-stress death for the good of the land AND the future of the horses still on the ranges.