Montana is looking to host a horse slaughterhouse. The last two in the U.S. were closed in 2007. Articles about it appear here and here. Slaughterhouses pose a number of problems - they are inherently inhumane, especially for horses, who have a lot of fear and a high flight drive. Stolen horses can be sold to slaughterhouses and killed before the owner can track them down. Meat from horse slaughterhouses is not something one should consume - often horses are fed dewormer or other medications which are not to be fed to animals intended for human consumption. There is no check at the kill house over ownership or what the horse ate.
While horse breeders complained when the slaughterhouses shut down, the good news is that breeding started to slow down. We don't actually need more horses - yet people keep creating them. In this market, hay prices are high and horses are being abandoned. Perhaps some will argue slaughter is more humane, but it's a gruesome end for the horse either way, one is just days of suffering vs. weeks or months. I don't mind seeing horse prices low - the market for horses will stabalize, it hasn't been long since the slaughterhouses closed and there are other forces in the economy at work right now. It would be nice to end up with an environment where people are more careful about breeding and more responsible about owning, rather than one where we return to the kill house as an "easy" answer.