I would like to build several predator-proof chicken tractors to house maybe 3-6 bantam cochins each. The predators I'd like to keep out are raccoons, foxes and dogs. Looking for tips on how to build such a thing, if it is even possible. I'd like to be able to go on vacation over the weekend and return with all my chickens intact without closing them up every night. I realize something stronger than chicken wire would be necessary - what type and gauge of wire would you recommend. I assume a double layer is a must. How far apart should the two layers be? How could I make the bottom edge impenetrable? If you have a link to a tractor that you consider predator-proof, I would love you to share it here.