I had a neighbor dog come over a few weeks ago. It was a large black lab, nothing huge or vicious. She just took a paw swipe at a pen I had that I was using chicken wire on. It came unraveled and tore a hole in it. Imagine if she was actually going after the chickens! At that point, she was just excited and interested in what was going on in the pen. I tore it all down a few days later and rebuilt the pen with hardware cloth and put up more wood supports and did it right. Which I should have done to begin with, but initially I was trying to save some $$$. I figured it wasn't worth it if I have to replace all the fencing, birds, etc if I had a real attack happen--- just do it right the first time. My main chicken run for the big coop is chain link fence with hardware cloth on the bottom half. So far, no issues.