I've even seen the mares crawl the fence to get to the stallion!
And, it's my understanding that for more than a century, Montana's open range law has allowed for the grazing of livestock where they have not been fenced out. The majority of Montana is considered open range. What this means is that if you do not want free roaming livestock on your property, you have responsibility for constructing and maintaining your own fence.
Montana law says that any of the following constitutes a legal fence. The fence is not under 44 inches and not over 48 inches in height. The fence is made up of a minimum of three horizontal, barbed wires that are well stretched. The lowest wire cannot be fewer than 15 inches or greater than 18 inches from ground level. The wire must be fastened securely to substantial posts that are set firmly in the ground, and these posts should be as nearly equal in distance apart as possible. Or, wires must be fastened to leaning posts that are well supported. Posts must be no farther apart than 20 feet. As an alternative, they can be 33 feet apart provided two or more pickets or stays provide additional support at equal distances between posts.
Fences can be made of a combination of standard woven wire and barbed wire under certain specifications. They can also be made of barbed wire, boards, rails or poles under specific dimensions and provisions. Under some circumstances, rivers, bluffs, hedges and mountain ridges constitute a fence.
Hopefully, you did your homework and checked into these laws before you purchased the property near Moon Creek.