In all cases, however, _thorough ventilation should be provided_; for of the two evils, of exposure to cold or of too great privation of air, the former is to be preferred. Sheep cannot long endure close confinement without injury. In all ordinary weather, a shed, closely boarded on three sides, with a light roof, is sufficient protection; especially if the open side is shielded from bleak winds, or leads into a well-inclosed yard. If the floors above are used for storage, they should be made tight, that no hay, chaff, or dust can fall upon the fleece. The sheds attached to the barn are not usually framed or silled, but are supported by some posts of durable timber set in the ground. The roofs are formed of boards battened with slats. The barn has generally no partitions within, and is entirely filled with hay. There are many situations in which open sheds are very liable to have snow drifted under them by certain winds, and they are subject in all severe gales to have the snow carried over them to fall down in large drifts in front, which gradually encroach on the sheltered space, and are very inconvenient, particularly when they thaw. For these reasons, many prefer sheep-houses covered on all sides, with the exception of a wide doorway for ingress and egress, and one or two windows for the necessary ventilation. They are convenient for yarding sheep, and the various processes for which this is required; as for shearing, marking, sorting, etc., and especially so for lambing-places, or the confinement of newly-shorn sheep in cold storms. They should have so much space that, in addition to the outside racks, others can be placed temporarily through the middle when required. The facts must not be overlooked--as bearing upon the question of shelter, even in the warmer regions of the country--that cold rains, or rains of any temperature, when immediately succeeded by cold or freezing weather, or cold, piercing winds, are more hurtful to sheep than even snow-storms; and that, consequently, sheep must be adequately guarded against them. [Illustration: A SHED OF RAILS.] SHEDS. The simplest and cheapest kind of shed is formed by poles or rails, the upper end resting on a strong horizontal pole supported by crotched posts set in the ground. It may be rendered rain-proof by pea-vines, straw, or pine boughs. In a region where timber is very cheap, planks or boards, of a sufficient thickness not to spring downward, and thus open the roof, battened with slats, may take the place of the poles and boughs; and they would make a tighter and more durable roof. If the lower ends of the boards or poles are raised a couple of feet from the ground, by placing a log under them, the shed will shelter more sheep.