Well, last night when I got home from work, there it was at its usual spot in front of my garage. I went in to change and kept an eye on it through the window, and waited for my co-worker to show up. About 20 minutes later (around 12:30), they did and the horse was gone! We looked all around the yard, went inside and waited about an hour, then looked again before giving up. The horse had disappeared, and this morning he was still gone. But as I was typing this, I looked out the window and he's back! Lol, I knew this would happen. This is why I did not post "Free Pony!" on craigslist. I will look into everyone's suggestions today. Thank you all, I didn't know there was such a thing as Equine Rescue or a local horse chapter. :thumbsup:
And yes Oliver, I agree that a probable slow death by abandonment is pretty cruel treatment.