There are somewhere around 90,000 head of horses in this country every year that no one wants and that does not include wild horses that the Bureau of Land Management is in charge of caring for/adopting out. The 90,000 figure is how many went to slaughter the year before the slaughterhouses were shut down a few years ago.
Anyone that doesn’t believe in horse slaughter needs to figure out how to solve that problem. Breeders are breeding too many and most of the excess comes from people who don’t intend to breed but are so ignorant they keep mares and studs together or have such sorry facilities they might as well put them together. Many of those horses are inbred and worthless for any use. Many are bred on purpose by folks that don’t understand horse breeding or the market conditions and think they can breed their inferior mare to a neighbor’s inferior stud and get the next show champion or Secretariat.
After the slaughterhouses were shut down, there was no market for the approx. 90,000 unwanted horses per year, many could not be sold because they were inferior, or crippled and no one wanted them at any price. Owners could not or would not feed them, dumped them or starved them in their backyard.
The BLM is having major problems with their wild horse program. All the folks that lobbied Congress to save them assured everyone there were tons of people who would adopt them. Nope, there are around 40,000 of them standing crowded in pens all over the US being fed and having their feet trimmed, vet care, etc.- all at taxpayer’s expense and their life is much like a person being in prison.
Anyone complaining about slaughterhouses needs to first find a solution to the problem of large numbers of unwanted horses.
Most of that number (excluding the BLM horses) exist now because there is a low end, always available market for them.
If there wasn't... most people would just do right by them. Those who don't.... there's solutions for that too.
The horse market does not rise and fall on the existence of slaughter as a cheap way out for horse owners.