I have ducks and have a move around pen. I am keeping it close to my garden and they usually spend quite a bit of time in the mud. They don't seem to go for the green stuff right now, just root around in the mud for bugs and worms. Look on my website to see my set up. I think the pen is under the DUCK tab and called NEW DIGS FOR THE DUCKS.
I saw the earlier post on the "chicken moat". I have a "Goat Moat". I have Tennesse Fainting Goats, which are not so aggressive in challenging fences due to their tendency to "faint" when startled. The most they do is put their front legs up on the fence to try and reach goodies on the other side, so I can use mere wooden snow fencing with sturdy metal fence posts at six foot intervals. This also keeps the neighbors entertained so they are hopefully less likely to complain about goats bleating and/or roosters crowing.
It also keeps the deer out, which have been a major problem here living as we do across the street from a nature preserve.
I hadn't thought about the chicken angle, but I would probably have to clip their wings to keep them from flying over the fences.
My next job is to figure out how to use the goats for the wider inside walking paths in the garden, which covers two acres. Right now I am fighting the weeds but the weeds are winning!