I read on the MOTHER EARTH NEWS website that you favor open-ended raised beds to allow easy access with a tiller. I also use open-ended (4-by-32-foot) fenced raised beds. My chickens till the compost in the beds for six months, and then I move them to the adjacent bed to till, weed, fertilize and remove insect pests.
Every six months, I close the “tilled” compost bed, plant it and call it a garden. At harvest time, I open the old garden for the chickens and pile grass clippings, leaves, old bedding from the deep-litter chicken coop, shredded paper and daily kitchen scraps 3 feet deep. In six months, it becomes a garden again. Maximum output, minimum input, and any weed seeds raised to the ideal planting depth become chicken feed.