For five years, there has been a moratorium against sending horses to slaughter in the U.S. Horses are taken to auctions where "kill buyers" buy them. While some of the horses may be old, sick or injured, many are young, healthy, and perfectly adoptable. The horses are then crammed together in trailers and hauled to the slaughterhouse. Once at the slaughterhouse, they are herded into holding pens. Depending upon when they arrive at the slaughterhouse, they may be run through chutes almost immediately, or they may be held until the next day - without food or water from the time they were loaded on the trucks, if not before. (Most auction houses do not automatically provide even water; if the seller decides to do so, that is up to them, but those horses aren't usually the ones who go to slaughter.)
Once they are run into the "kill room," the method of killing varies depending upon the slaughterhouse. The killer may use "bolt guns," where a metal bolt is driven through the horse's skull into the brain. The horse may be shot with a firearm (hopefully the killer has good aim and the horse doesn't flinch). Other methods may be used, usually depending upon what is cheapest.
The meat resulting from all of this isn't necessarily used, as many people think, in dog food. Much of it is shipped to Europe for human consumption.
There is little, if anything, about this whole sequence of events that is humane. If dogs, cats, or other smaller companion animals were treated this way, there would be front-page newspaper articles and items on the evening news. Because these are horses, "farm animals," many people pay little attention or don't really care about how they are treated (or mistreated). This needs to change, preferably from the President down. We don't just need a moratorium against sending horses to slaughter. We need federal legislature banning it in perpetuity. On behalf of our own Ace and Brandie, thank you for taking time to read this.
P.S. A former Kentucky Derby winner, who happened to be a gelding, was sent to slaughter when he was no longer profitable. By the time anyone knew about his custodian's plans for him, it was too late to rescue him. I should remember his name but don't; however, I'm certain that it was prior to Funny Cide's win in 2004 or 2005.