My friend and I had seen "Beware of Dog" signs posted along the perimeter but didn't see or hear anything. We thought that they were just there to scare people, just like "No Trespassing" signs (haha) so we hopped the fence anyway. I was checking out a part of the winery when my friend ran back and told me that she saw two cars parked on the other side. Since it took us 20 minutes to climb over, we really didn't want to leave right away. There was still a lot to explore so we went the opposite direction and walked around taking photos. When the sun set, we heard the property owners' engines start and saw them drive off. That's when I heard the sound of something running. My friend and I were being idiots standing next to the fence for several minutes worrying about hurting our feet if we jumped onto the sidewalk. She didn't believe me when I told her that they set something loose. 2 minutes later, a medium sized dog charged at us and barked like crazy. The three of us made a lot of noise for what seemed like forever. Once we realized it wasn't going to bite us, we just kind of stood there trying to talk to it. It wouldn't stop barking but soon lost interest and ran back. That's when we grew the balls to jump over and escape!

My guess is the owners only set the pup out when they're not on the property. Maybe bring some milk bones if you go!