Tiny Farms post about chicken tractors. Yes, "chicken tractors", which our family calls "the chicken Fort Knox."
These are mobile chicken houses, basically, built of lightweight metal. They protect the critters within, but are open on the bottom, which lets the birds scratch up the soil and, ah, enrich it with their fine leavings. The "tractor" is mobile, being light and equipped with wheels. After a time, we haul the thing to a new spot, leaving a rectangle of nicely improved earth. Very neat.
Reading this now, in the deep of winter, is bittersweet. I badly want the snow to be gone, so we can dig out our tractor. It needs a little repair - one sheet of metal got whacked by a falling tree limb. It needs more chickens (we're down to one). But the sweetness comes from thinking of the sheer elegance and practicality of the thing, the though of soil growing, the happy industry of the birds. It draws my imagination forward to warmer times.