I built on 14 acres with no thought to having a horse, so I don't count my land costs. Figuring around $400 for hay and miscellaneous feed (November through March), $250 for the vet, maybe another $150 for salt, minerals, worming tubes, and then maybe another $400 for maintaining the fences, the run-in shed, and electricity for the 1500 watt heater that keeps their water liquid when it's -30. I do my own trimming. That totals about $100/month for my two horses, or $50/month each. I've had horses for over 15 years now and except for the year I rented a trailer and hauled out to Washington State, I don't think I would quite come up to average that $1200/year.