This article was published in the April/May 2007 issue of Backyard Poultry Magazine.
It was added to the site December 15, 2008.
My Greenhouse Renovation
In the late summer and early fall of 2005, I had to replace the rotting foundation boards around the perimeter of my 20×48-ft greenhouse. Since I planned to replace them with concrete blocks, I decided to take the opportunity to make two other changes in the greenhouse as well: to put in place a serious vermicomposting operation—and to install two 8×8-ft pens for housing chickens in the winter greenhouse.
I had been vermicomposting for several years in a 3×4-ft “worms eat my garbage” style worm bin in the greenhouse. But I wanted to scale up, to process organic “wastes” by the pickup load using worms, obtaining in the process an abundance of earthworm castings (excreta) as a major component of our garden fertility program; but also a regular harvest of worms to feed the birds. The greenhouse renovation presented the opportunity to scale up indeed: I installed five 4×8-ft worm bins down the center of the greenhouse, with heavy lids (¾-inch plywood on 2×4 framing) over which I routinely push a fully-loaded wheelbarrow. Bins are made of two courses of 4-inch hollow concrete block, thus are 16 inches deep. That’s a lot of vermicomposting volume. Since I need a center aisle in the greenhouse anyway, I didn’t lose any significant amount of growing space to the worm bins.
Similarly, I used two courses of 4-inch block as the perimeter for two 8×8-ft chicken pens in the north end of the greenhouse. (Greenhouses typically are oriented east-west. That was not possible in my situation; but the north-south alignment actually works to advantage in this case: The framing for the chicken pens does not block light into the interior during the winter growing period.) The two pens are on opposite sides of the end worm bin, each with its own door. It is possible to keep two greenhouse flocks, separated from each other, if I wish, releasing them to the outside on alternate days. Or I can open both doors and allow use of the two pens as one space, releasing all the birds to the outside. In either case, however, either pen door serves double duty: When the pen is open, its door latches into position to block access into the interior of the greenhouse, where the winter vegetable crops are growing.
The New Greenhouse in Practice
I had long considered moving chickens into the greenhouse for the winter, assuming the added body heat would help moderate the frigid overnight temperatures. I have no way to measure the degree to which it has done so, but I currently have 43 chickens, 3 Buff Ducks, and 2 African Geese ensconced there, and have to believe that’s a fair amount of warmth inside the greenhouse that otherwise would not be present.
Another contribution I assumed the flock would make is the increased carbon dioxide exhaled by the birds, which is taken up by the plants as an essential step in their metabolism (conversion of sunlight to food energy). I’ve read that in Holland, some growers buy bottled CO2 to pump into their greenhouses. I figured I could get the same effect with chicken breath. Again, I have no way to measure enhanced plant growth, if any.
Since the openings to the pens are exactly four feet wide, either pen door can be latched into position between the two pens, blocking access into the rest of the greenhouse interior. Initially I had a few rogue fliers go over the door, and wreck havoc among the lettuces and chicories. A session of wing-clipping put a stop to that impudence.
But that is not to say they didn’t enjoy the bounty of the winter greenhouse as much as we did. A 20×40-ft growing space is more than Ellen and I need to keep us in winter salads and cooking greens, so I always grow cut-and-come-again green forage for the flock as well—mixed grain grasses (rye, oats, wheat, barley), crucifers (rape, mustard, turnip), and peas. Even small amounts of these greens provide a significant boost in vitamins and enzymes.
As for the worm bins, I filled them with “pony poop” hauled in by the pickup load from a neighbor who breeds and boards horses. Though it took longer than I expected for the population levels to build to their current levels, the worms are now processing the manure rapidly, and I am harvesting worms regularly to feed to the flock. I simply dig out one or two five-gallon buckets of the bedding itself, after it is well broken down by the worms, but before conversion to pure castings (at which point it would no longer contain any worms). I simply dump that bedding out, either onto the deep litter in the chicken pens, or onto the thick mulch over the winter yard outside (more of that below). The chickens snap up the worms, in the process scratching the mix of bedding and castings into the litter or mulch, which keeps it from drying out. Thus I assume the teeming populations of microbes in the worm castings remain alive, ready to boost the soil food web when the litter is used in the garden come spring.
Note that, in the protection of a bin dug 16 inches into the earth, inside a greenhouse, feeding activity by the worms, as well as reproduction, continue despite the chill outside. (Note also that in the summer, when no chickens are in residence in the greenhouse, their two pens provide an additional 128 sq ft of worm bins for processing more pony poop.)
Access to a Winter Yard
A major reason for introducing the chickens to the greenhouse was to resolve a dilemma that has always dogged my winter management strategy: I don’t like confining my birds, I want to give them maximum access to the exercise, fresh air, and sunshine available outside—not keep them cooped up inside the winter house, however much space I allow per bird; and despite the fact that the deep organic litter there provides the best possible solution to several winter care needs.
But on the other hand, I cannot release the birds onto a dormant pasture sod, which they would quickly strip. I don’t have to picture for you the nightmare that would follow: an accumulating coating of droppings over a plot of frozen dirt, eager to run for the nearest stream, lake, or estuary with the first rain.
The north door of the greenhouse opens onto a garden area. That is to say, an area not in pasture sod, an area that could benefit from the winter management strategies I have put in place for two winters now. I started in the late summer and early fall: As soon as I took the last harvest off any garden bed, I planted a cover crop appropriate to that point in the season—small grains, peas, mixed crucifers. By the time I moved the mixed winter flock into the greenhouse pens, every garden bed was lush with thick green cover. I enclosed the greenhouse garden area in an electronet perimeter. When I released the greenhouse flock onto that Eden, they ate as well as they had at any point in the season, gorging not only on the fresh green forage, but on live animal foods there as well—earthworms, slugs, and insects.
The disappearance of the last of the green signaled the next stage in the strategy: I mulched those garden areas heavily with round bales of spoiled hay. I bought the hay as a purchased input, but only because a dry summer prevented my getting a fall cutting of grass off the pasture for mulching. In a more generous season, I would not have needed the outside input. Still, the mulch hay was cheap: $10 per 800-lb bale, loaded on my pickup. With round bales, it was easy (and fun!) simply to kick them off the pickup and roll them out.
Now, I can hear many of my more savvy readers protesting: “Hay? Are you nuts?! You’re bringing in a huge load of seeds.” Oh my yes, am I not indeed. And those seeds are available to my birds, who spend all their waking time going after them. As late winter edges into early spring, they begin to sprout, becoming an even more valuable food source. Last spring, I did not have a significant weed problem as a result of the hay mulch.
I don’t know how deep an organic mulch you would need in your area to keep the ground from freezing, but in mine (Zone 7a), I find that a six- to eight-inch mulch is deep enough. Keeping the ground from freezing is another part of my strategy: As a result, earthworms, slugs, and other soil-line critters remain available to the tirelessly-scratching chickens. More free, high quality food on their “table.”
I urge you to experiment with a heavily mulched winter yard such as I describe. For me, this year, spoiled hay was the ideal mulch. In another year I might use cuttings from the pasture, or leaves from a neighbor’s dozen big white oaks. In your area, you might find agricultural “refuse” at low cost, or free for the hauling. Corn stover or soybean vines from threshing operations; crushed corn cobs from milling; peanut or buckwheat hulls—take advantage of local possibilities.
The key to homesteading success is finding creative ways to make one project serve multiple functions. Note how my “chooks in the greenhouse” strategy neatly answers many needs: It provides winter housing for the flock. Body heat and exhaled CO2 benefit the plants growing in the greenhouse. The green forage crops and worm bins inside the greenhouse provide live, natural food for the birds. The mulched yard outside provides additional access to self-harvested, high quality foods. The thick organic duff the birds are working absorbs the poops laid down, preventing their runoff into water systems, where they can be deadly, and recaptures their fertility for use on the homestead’s gardens, orchard, and pasture. At the end of the winter, large quantities of mulch remain for use in the garden; but so finely shredded it is ideal even for small-seeded, closely planted crops like carrots. And remember that the winter yard itself is a garden: Protected by the heavy mulch cover, the soil remains in beautiful condition, ready to plant without tillage, its microbial populations at full stride because of the protection from winter’s extremes, as well as the boost from the worm castings and the flock’s droppings.
With regard to the aforesaid droppings: It is recommended that you allow 60 days from the time raw poultry manure was laid down on the site before harvesting crops close to the ground like radishes or lettuce. Frankly, I doubt that manure from a well-managed homestead flock poses much of a hazard. (Joel Salatin sent samples of his dressed poultry and his poultry’s manure off to the same lab for testing, and both samples were reported as pathogen-free.) Last year I simply planted the spring garden in that space and harvested when the crops were ready. Still, I must give you the official point of view on the matter.