We are not currently doing any rescuing, but we work with local rescues. We have helped train 3 rescue horses from Changing Fates along with other owners of rescue horses through the SPCA. I personally try to rescue by keeping an eye out for free horses which usually get taken to new Holland.
Getting a horse is a huge responsibility which I can help you prepare for, but if you don't have the time or you think this is just another pet please understand they are family for life and if you ever need to sell or re-home research is the key to help prevent them from going to auction.
Once a horse is bought for slaughter at an auction (such as New Holland,) they are loaded onto a double decker horse trailer, where 20+ horses are crammed together regardless of sex or age. Many are trampled and severely injured by the time they arrive at the slaughter plant (which is out of the country.) There are no food or water breaks during their shipping. If they are too weak or injured to walk out of the trailer, a wench will be used to drag them out by their legs.
Consider adopting a rescue dog from Whimsical animal rescue and if you can care for them, then maybe a horse is for you.