The last two or three years, as we use the chickens more and more to graze green manures, weed fallow beds, or stir sheet compost, winter has found us with birds in the gardens, either in tractors, which we cover with plastic sheeting when the weather gets really cold, or under low tunnels, cleaning up after we’ve harvested whatever was growing in there.  This has worked well so far, and not only for the garden services provided:  we find that chickens in moveable pens need less feed, even in winter, apparently finding things to eat in their daily allotment of garden soil; also, for some reason it is these birds, the ones under plastic, who lay the most eggs in winter.  No supplemental light, no heat (except the solar heat trapped under the plastic film), but more eggs.  Right now the three dozen birds moving over the gardens at the monastery are laying at something more than 25%.  Maybe that doesn’t impress anyone whose poultry have constant access to commercial corn-and-soy pellets or crumbles, but our birds eat a much cheaper home mix of fermented wheat, oats, barley, sunflower seeds and millet, supplemented with whatever protein supplement the farm has on hand, mostly milk in one form or another — and almost 30% lay at the winter solstice seems to us a pretty good score.