I made a modification to the concept of a chicken tractor (movable pen) in order to more efficiently accommodate one in my garden. Instead of a pen that I move around the garden, I divided my garden into three sections, and put a coop that has access to each of the sections in the center. I use one section each year to raise chickens (like crop rotation).
When it comes time to plant my crops, I move the chickens to another section. Then I buy several round bales of hay or straw, and unroll them in the garden, leaving a small gap between for planting seeds. This takes care of the problem of mulching, and when the garden is finished producing vegetables for the season, the chickens have a field day scratching in the remnants.
New London, North Carolina