The dogs don't dig as much as the chickens do!

Ok, I might look like I have no idea on chickens, but I can tell you in all my reading and studying chicken keeping I have never seen where chickens dig out off their coop! Mine did it again today! The last escape I thought was by accident. I thought the dust bath was just too close to a low lying place in the ground and they got out. Today I think they know!!! They made a "hole" under the front of the fence. It is crazy. We looked into the yard and saw them out. I redid their netting before my trip and knew they would be safe now...guess I was wrong! So in addition to us building a new frame for the netting over the  ~10x24 yard, we now have to work on the lower part of the fence. I wonder if this is normal chicken behavior or we have a gang of chicken bandits! lol.  They are fun, just way more interactive than I ever thought!