Horse Zoning 
Whether running a business or just enjoying a few pasture pets, it is important for the horse owner to be aware of important legal issues to keep this dream from turning bad.
Generally, there are two set of rules that may affect you: Zoning and Homeowner's Assosiations (HOA).
Zoning rules are defined by your local or state government and affect the methods in which you are permitted to develop and utilize your land. Zoning laws will affect what buildings you can build, where they can be located on the property, whether you can have a business situated on the property, etc.
Homeowner's Associations are generally formed when a piece of land is subdivided and covenants are attached to the property concerning the use of the land. These covenants are usually more restrictive than zoning law -- sometimes even addressing the color of your house, fence construction and animal care.
To find out about zoning laws governing your property, you should make a trip to your local government building. The tax office is usually a great place to start any fact finding mission when it comes to your land. Your parcel should have a unique tax identifier that will likely be used throughout the government's records. Also, the tax office can probably tell you your deed book and page -- this is where the deed of trust showing your property ownership is recorded.
Once you have your parcel information, you'll need to find the planning department. This will be where you can learn the rules that apply to your parcel. Also, they can show you how to obtain any permits you may need.
Next, check to see if you live in a subdivision that has covenants restricting the use of your property. This information can usually be found from your homeowner's association. If you do not have an active homeowner's association, check with your county's register of deeds.
When you get a copy of the covenants, read it to see if there are any restrictions on pets, livestock, out buildings, barns, fences, trailer parking, etc. You'll need to ensure that any changes you make to the property are within the terms of the covenant. If you want to have a business, check to make sure that you are not prohibited. Check to ensure that you are permitted to have customers come to your farm. If you have any questions, take it up at the next association meeting.
If your homeowner's association prohibits your plans, go to the next meeting and ask if the rules can be changed. You also may want to volunteer to join the committee or aid with association business. If you encounter resistance, consult with a lawyer. In many cases, association covenants are not filed and attached to your deed properly. A lawyer may be able to fight against unreasonable rules.