The mules don't like being tied up and can't lay down and roll so I just picked up some components for a portable electric fence. I set it up in the pasture where I keep the mules. I ran a single ribbon of tape at about 40". First mule got zapped and immediately started thinking. She went to the gate where she go in and stared at the ribbon for about 10 seconds and squeezed right under it and got out. What a stinker! I ran a second ribbon below the first and put both mules in and left them overnight. We'll see if they're still in there this morning.