GreyRay, you also need to be looking at how the land is listed.
If it doesn't have an ag listing you won't be able to put livestock on it, regardless of the amount of acreage.
If it's in a subdivision, I can tell you right now you won't be able to put horses on it.
Besides, why would you want to put up fencing on a rented property? You're only increasing the value of it for the owner, not yourself.
Before you and your family get all gung ho about a particular place, you'd better find out what the covenants and restrictions are, as well as whether or not you can put horses on it.
Never trust what a R/E agent tells you concerning livestock; always do your own research.