Yes, you really need a solid fence. Pyrs will roam if not in a fenced yard. These dogs were bred to watch over flocks in mountain pastures. They would rather explore what is on the other side of the hill than listen to a human command to “Come!” If you’re going to own a Pyr, a fenced in area is a must. Invisible fences and Pyrs do not do well. Most Pyrs will endure the electric jolt to go patrol the neighborhoods but not to get back in.