The Omnivore's Dilemma - Michael Pollan [108]
After we had finished watering and feeding the broilers, I headed up to the next pasture, where I could hear a tractor idling. Galen had told me Joel was moving the Eggmobile, an operation I’d been eager to watch. The Eggmobile, one of Joel’s proudest innovations, is a ramshackle cross between a henhouse and a prairie schooner. Housing four hundred laying hens, this rickety old covered wagon has hinged nesting boxes lined up like saddlebags on either side, allowing someone to retrieve eggs from the outside. I’d first laid eyes on the Eggmobile the night before, parked a couple of paddocks away from the cattle herd. The hens had already climbed the little ramp into the safety of the coop for the night, and before we went down to dinner Joel had latched the trapdoor behind them. Now it was time to move them into a fresh paddock, and Joel was bolting the Eggmobile to the hitch of his tractor. It wasn’t quite 7:00 A. M. yet, but Joel seemed delighted to have someone to talk to, holding forth being one of his greatest pleasures.
“In nature you’ll always find birds following herbivores,” Joel explained, when I asked him for the theory behind the Eggmobile. “The egret perched on the rhino’s nose, the pheasants and turkeys trailing after the bison—that’s a symbiotic relationship we’re trying to imitate.” In each case the birds dine on the insects that would otherwise bother the herbivore; they also pick insect larvae and parasites out of the animal’s droppings, breaking the cycle of infestation and disease. “To mimic this symbiosis on a domestic scale, we follow the cattle in their rotation with the Eggmobile. I call these gals our sanitation crew.”
Joel climbed onto the tractor, threw it into gear, and slowly towed the rickety contraption fifty yards or so across the meadow to a paddock the cattle had vacated three days earlier. It seems the chickens eschew fresh manure, so he waits three or four days before bringing them in—but not a day longer. That’s because the fly larvae in the manure are on a four-day cycle, he explained. “Three days is ideal. That gives the grubs a chance to fatten up nicely, the way the hens like them, but not quite long enough to hatch into flies.” The result is prodigious amounts of protein for the hens, the insects supplying as much as a third of their total diet—and making their eggs unusually rich and tasty. By means of this simple little management trick, Joel is able to use his cattle’s waste to “grow” large quantities of high-protein chicken feed for free; he says this trims his cost of producing eggs by twenty-five cents per dozen. (Very much his accountant father’s son, Joel can tell you the exact economic implication of every synergy on the farm.) The cows further oblige the chickens by shearing the grass; chickens can’t navigate in grass more than about six inches tall.
After Joel had maneuvered the Eggmobile into position, he opened the trapdoor, and an eager, gossipy procession of Barred Rocks, Rhode Island Reds, and New Hampshire Whites filed down the little ramp, fanning out across the pasture. The hens picked at the grasses, especially the clover, but mainly they were all over the cowpats, doing this frantic backward-stepping break-dance with their claws to scratch apart the caked manure and expose the meaty morsels within. Unfolding here before us, I realized, was a most impressive form of alchemy: cowpatties in the process of being transformed into exceptionally tasty eggs.
“I’m convinced an Eggmobile would be worth it even if the chickens never laid a single egg. These birds do a more effective job of sanitizing a pasture than anything human, mechanical, or chemical, and the chickens love doing it.” Because of the Eggmobile, Joel doesn’t have to run his cattle through a headgate to slather Ivomectrin, a systemic paraciticide, on their hides or worm them with toxic