For the roof, tiles or slates alone are not sufficient, but, if used, must have a boarding or ceiling under them; otherwise all the heat generated by the fowls will escape through the numerous interstices, and it will be next to impossible to keep the house warm in winter. A corrugated roof of galvanised iron may be used instead, but a ceiling also will be absolutely necessary for the sake of warmth. A rough ceiling of lath and plaster not only preserves the warmth generated by the fowls and keeps out the cold, but has the great advantage of being easily lime-washed, an operation that should be performed at least four or five times a year. Boards alone make a very good and cheap roof. They may be laid either horizontally, one plank overlapping the other, and the whole well tarred two or three times, and once every autumn afterwards; or they may be laid perpendicularly side by side, fitting closely, in which case they should be well tarred, then covered with old sheeting, waste calico, or thick brown paper tightly stretched over it, and afterwards brushed over with hot tar, or a mixture of tar boiled with a little lime, and applied while hot; this, soaking through the calico, cements it to the roof, and makes it waterproof. But board covered with patent felt, and tarred once a year, is the best. The roof ought to project considerably beyond the walls, in order to prevent the rain from dripping down them. Ventilation is most important, and the house should be high, especially if there are many fowls, for by having it lofty a current of air can pass through it far above the level of the fowls, and purify the atmosphere without causing a draught near them. They very much dislike a draught, and will alter their positions to avoid it, and if unable to do so, will seek another roosting-place. Ventilation may be obtained by leaving out some bricks in the wall or making holes in the boarding; and when there is a shed at the side of the fowl-house, by boring a few holes near the top of the wall next to the shed; all ventilators should be considerably above the perches, in order to avoid a draught near to the fowls; and should be entirely closed at night in severe weather. The best method of ventilation for a fowl-house of sufficient size and height, is by means of an opening in the highest part of the roof, covered with a lantern of laths or narrow boards, placed one over the other in a slanting position, with a small space between them like Venetian blinds. Light is essential, not only for the health of the fowls, but in order that the state of the house may be seen, and the floor and perches may be well cleansed. It may be admitted either through a common window, a pane or two of thick glass placed in the sides, or glass tiles in the roof. It also induces them to take shelter there in rough weather.