Just curious as to why you bought a horse farm (not
a ranch) and don't have any plans to buy horses yourself. I'd never spend money on something I didn't have any intention of using for myself. Very interesting and rather strange purchase, to my way of thinking.
As far as offering complete self care, you'd still be responsible for keeping the fences and property maintained properly. You'll also need major liability insurance, since you'd be letting strangers and their equines onto your property. Regular homeowner's won't cover the insurance you need if you rent out the facility to boarders or even just one other person.
Are you prepared to let people come and go on your property at all hours of the day and night? Because that does happen when it's self care. You also need to be aware that even if it's completely self care, you'll be ultimately responsible for any animal neglected by its owner, since it's on your property.