I've heard that mini goats are harder to contain, but we never had an issue with our standards. The babies, on the other hand, escaped all the time! I've attached an old photo of my dad, big brother and I with our old sheep, Annie. You can see the fencing in the background. Nothing special and it contained them just fine. They did occasionally bust boards rubbing on it.
Sheep are definitely easier to handle, but they just don't have the personality of goats. Excellent lawn mowers, though!
View attachment 1647461