I've got an ongoing arms race with mine. They learn new ways to escape, I have to figure out how the went and block them. Got 'em foiled for the moment, but I saw one rooster trying to pull staples today. Think I need to nail in some old fashioned fence staples. Also watched one climb up the fence, feet over beak like a darn parrot. Put im in the roaster before he could teach the others.
I found laying down some lanscape rock, covering with loose clay, wetting and allowing to dry foiled the digging effectively.