When you have a small area where a horse is kept, your fence will take a beating. I keep mine (4 horses) on a 1.5-2 acre dry lot in the winter or when I need to take them off the pasture. I put up good quality woven wire horse fence. They have it leaned over almost all the way around. Do yourself and your fence a favor and put the hot wire in. I didn't and regret it.
The dry or sacrifice lot is a good way to manage pasture too. My girls go to the lot whenever my pasture is stressed, muddy, or the weather is bad. I feed hay during that time. Good luck and enjoy your new adventure