I've always wanted a chicken tractor, and now can add a chicken moat to my chicken wish list (along with the chickens, sadly). Apparently, the double fencing also keeps quite a few critters (like deer) out of the garden because they don't like to pass through such a confined area. And the chickens eat any and all bugs that have to cross the run to get at your vegetables.
I adore the idea. Though I wonder if this will have to wait until we trade in our suburban farm for a real farm.
As I followed links around the internet for this, I came full circle and ended up in the archives of one of the blogs on my blogroll, One Straw. I guess I shouldn't be surprised since all of us great minds must think alike.
Chicken tractors and moats for all!