By Herman Joseph
The floor is extremely important. An ideal floor for a deep litter house is well drained and made of concrete, with a layer of heavy gravel or wire mesh embedded in it to keep out rats. This type of floor is usually costly. Wood, bamboo, bricks or large flat stones (according to what is locally available) can be used, but are harder to clean.
Clay floors are cheaper, but require the application of a fresh layer of clay either between flock batches or at least annually.
In areas where construction materials are cheaper than deep litter, and particularly in humid regions where litter material is not available, raised floors are sometimes used. These are made of wire mesh, expanded metal, wooden slats or split bamboo, to allow the droppings to collect under the house, and should be about one metre above the ground to allow for cleaning and ventilation.
Higher floors may result in an unstable building. They are supported by pillars, which are either rot-resistant or have stone or concrete footings, and which are made of such materials as wood, bamboo, oil drums and concrete blocks. Houses with raised floors on posts can be protected against rats with baffles.
The baffles can be made of a metal collar, a tin can turned upside down or a metal band wound around the post, but must fit tightly to deter even the smallest rodent.
The roof and walls of the house can be made of any inexpensive local material, including bamboo slats, sorghum stalks, mud, wooden slats and palm fronds, as long as the structure is made relatively rat-proof.
In colder regions, the walls should be thicker or insulated, but in warmer climates thatch can be used, although it should be replaced frequently to minimize parasite and disease problems. The inside of the walls should be as smooth as possible, to prevent tick and mite infestation and to make cleaning easier. Interior length-ways building partitions are not advisable, as they reduce cross-flow ventilation.
The roof should be watertight, and should overhang the walls by one metre if the windows have no shutters. The roof can be made of thatch, sheet metal or tiles. Thatch is usually the cheapest option and provides good insulation. It will probably have to be replaced every three years, or immediately if ticks get into it.
It should be interlaced with bamboo or wooden slats to keep predators out. Sheet metal is usually too expensive, and in hot climates must be painted with white or aluminium to reflect sun heat.
However, it is easily cleaned which is an important advantage where ticks are a problem. A layer of plastic sheeting sandwiched between bamboo slats is a good seal against rain and vermin. Flattened oil drums can be used at a lower cost. Although usually more expensive than thatch, sun- or oven-baked tiles will last much longer. Because of their weight, the frame for a tiled roof must be stronger than for other materials.
Window design depends on the local climate. Chickens need more ventilation than humans, but should be sheltered from wind, dust and rain. During storms, wood or bamboo hinged shutters or curtains made from feed sacks can cover window openings on the windward side of the house. In humid climates, window design should take as much advantage of the wind direction as possible to reduce the amount of moisture in the house. Window areas are best covered by wire mesh or expanded metal. Wooden slats or bamboo can be used, depending on available funds and materials. However, the thicker the material, the more ventilation will be reduced. Doors should be made of metal, wood or bamboo. The top half of the door could be wire mesh. Doors should be sufficiently strong to withstand being opened and closed many times a year.
Gabled roofs reduce solar heat loading when compared with flat or lean-to roofs. The pitch or “angle of rise” on a gabled roof is important for many reasons. Traditional village thatched gabled roofs are usually constructed using bush timber, and at a steeply pitched angle (greater than 42° from the horizontal), which helps the roof to withstand stormy winds. Shallower pitched roofs are more susceptible to being blown off in strong winds, particularly when the pitch angle is 15° to 20°. Shallower pitched roofs have less roof surface area, which reduces the cost of surfacing material, but because they are more affected by stormy winds, they need stronger support frames, which results in a much higher overall roof cost. A 42° pitch is the optimum compromise between roof surfacing costs and roof support costs.
The maximum width for an open-sided poultry building, under conditions of a slight breeze, which allows air movement across the shed at the height of the bird, is 8 m (26 ft). To maximise the volume and velocity of airflow across the shed width, the end walls of the shed should be closed. This forces the air to flow across the shed width, especially if the wind is not already coming from that side. Centre ridge ventilation is not recommended, as it discourages airflow across the full shed width. Air enters at the prevailing wind side and is drawn up at the centre to exit at the ridge, excluding the other half of the building.