Semi-intensive Systems

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Semi-intensive systems are commonly used by small scale producers and are characterized by having one or more pens in which the birds can forage on natural vegetation and insects to supplement the feed supplied. It is desirable to provide at least two runs for alternating use to avoid build up of disease and parasites. Each run should allow at least 10 to 15m² per hen and be fenced, but a free-range allowing 40 to 80m² per hen will be required where the hens are expected to obtain a substantial part of their diet by foraging. A small, simple house, which allows 0.3 to 0.4m² per bird, and which has a thatched roof a littered earth floor and slatted or chicken wire walls on at least three side will provide protection from inclement weather, from predators at night and offer shade in the daytime. The shelter should be large enough to enter to collect eggs and be equipped with nextboxes, feeders, drinkers and perches. For convenience the house should be situated so that access to each of the runs can be provided with small outlet doors or 'popholes'.

Figure 10.38 shows another type of shelter for roosting and laying, which can be used in combination with daytime foraging by the hens. The legs of this structure have rat guards and ant protection and may be equipped with skids or wheels to make the whole unit easily movable between runs. Feed and water are provided in troughs outside the house.

This system is low in cost, but growth of the birds and egg production are likely to be less than with systems offering closer confinement and better feed. Losses may be encountered by birds of prey and from failure to find eggs laid in bushy areas. The poultry run requires a considerable amount of fencing.

A fold unit is a house and run combined, having part of it covered with chicken wire and the remainder with solid walls. The unit should allow 0.5m² per bird and must be moved each day over an area of grassland. A unit 6 by 1.5m will take 16 to 18 birds and can normally be handled by one man. For larger flocks several such units will be used. Portable units are generally more expensive than permanent houses and may decay quickly because of the contact with the ground. The hens have reasonable protection against birds of prey and inclement weather, and parasites, if the unit is not returned to the same area within 30 days.

In areas where grassland is limited a yard deeply littered with straw and allowing only 0.4 to 0.7m² per bird will provide for an outdoor exercise area. This system is similar to the deep litter system, but requires more space, a considerable amount of litter for the yard and the fresh green food has to be carried to the birds.

Figure 10.38 Poultry shelter for 50 layers.

Figure 10.39 Fold unit for /8 layers.

Deep Litter System

Deep litter houses, Figure 10.40, confine the birds in a building that offers good protection with a reasonable investment. If well designed with low masonry walls set on a concrete floor and wire mesh completing the upper part of the walls, the building will exclude rats and birds.

The principal advantages of this system are easy access for feeding, watering and egg gathering, good protection and reasonable investment. The principal disadvantage is the need for high quality litter. If this is produced by the owner, it is of little significance, but if it must be purchased, it becomes an economic factor. In either case, the litter and manure must be removed periodically.

The deep litter house can be designed up to 9m in width and any length that is needed. Approximately 4 to 5 birds/ m² of floor area is a satisfactory density.

Slatted or Wire Floor System

Figure 10.40 Deep litter house for 130 layers (or 350 broilers). Note the solid wall facing the prevailing wind.

A small house of this type with slatted floor is shown in Figure 10.41. Alternatively wire mesh can be used for the floor. It is built on treated wooden piers 0.8 to 1m above the ground. Ventilation and manure removal are both facilitated, no litter is required and bird density can be 6 to 8 per m². Feeding, watering and egg gathering are all efficiently handled from the outside. Either a double pitch thatch roof or a single pitch corrugated steel roof may be installed with the eaves about 1.5m above the floor. If the latter is used, some insulation under the roof is desirable. The feed troughs should be equipped with hinged covers and rat guards should be installed at the top of each pier. The width of this type of building should be limited to about 2m to allow easy removal of manure and adequate wall space for feed and nests. The building should be oriented east and west and may be of any length. However, if it is more than 5m long, nests will need to be put on the sides and all remaining wall space on either side used for feeders in order to allow the required 100mm/bird. See Table 10.13.

If using a slatted floor' made sufficiently strong for a person to walk on, then a wider building is feasible as feeders can be placed completely inside where the chickens have access to both sides of the trough. The floor is sectioned for easy removal during cleaning out of manure.

This type of houses is said to be cooler than other types, but the building cost is high and management is more complicated.

Figure 10.41 Slatted floor house for 50 layers.

Combination of Slatted Floor and Deep Litter

A combination deep litter, slatted floor house, offers some advantages over a simple deep litter house, but with some increase in investment. Figure 10.42 shows a house of this type for the small producer.

Approximately l/2 of the floor area is covered with small gum pole slats or with wire mesh. This area is raised above the concrete floor 0.5m or more so that cleaning under the slatted portion may be done from the outside. Waterers and feeders are placed on the slatted area. This type of house is limited in width to 3 to 4m so that feeders and waterers can be handled from the litter area and manure beneath the slatted area can be easily removed from the outside without moving the slats or disturbing the birds. Although this system entails added expense for materials and labour to install the slats, the bird density can be increased to 5 to 7 per m², so there is little difference in the cost per bird. This system saves on litter, increases litter life, reduces contact between birds and manure, and allows manure removal without disturbing the hens. Ventilation is improved due to the slatted floor. Perhaps the biggest disadvantage is the limited width for convenient operation and the need for some litter.

In medium to large scale houses of this type the slatted floor must be made removable in sections and at least part of it made strong enough to walk on. An increased building cost and a more complicated management will result, however. The house shown in Figure 10.43 has slats over 2/3 of the floor area. This is generally considered maximum for this type of house and allows for a stocking density of up to 8 birds per m². Automatic tube feeders are placed on the slatted floor. One such feeder, with a bottom diameter of 0.6m can serve for 60 to 75 birds, depending on size of breed. The water troughs are suspended from the ceiling. The nestboxes are doubled by arranging them back-toback and have one end resting on the slatted floor and the other suspended from the ceiling. Egg collection can be facilitated by the use of a trolley, which is supported on a rail just below the ceiling. Cleaning out between batches can be done by a tractor shovel, if all furnishings and part of the end walls are made removable.

Figure 10.42 Poultry house fot 40 layers half deep litter/ half slatted floor.

Figure 10.43 Poultry house with l/3 deep litter and 2/3 slatted floor for 1100 to 1200 layers.

Cage or Battery Systems

Cage management of layers in very large, well insulated, windowless buildings has become the standard practice in much of Europe and the colder parts of the United States. With complete mechanization of feed, water, egg collection, manure removal and environmental control, two to three people can care for thousands of birds.

It should be noted that a very large investment is made in order to obtain labour efficiency and ideal environmental conditions. East and South-East Africa has relatively low labour costs and a mild climate making a mechanized cage system in an insulated building unnecessary and impractical.

Nevertheless, there are much simpler cage systems that may work very well for commercial growers in this region. These consist of rows of stair-step cages in long narrow shelters. Figure 10.44. The thatch roof or insulated metal roof shelter can be completely open on the sides with perhaps some hessian curtains in areas where cold winds are experienced. The buildings should be oriented east and west and designed to provide shade for the cages near the ends.

A 3.4 metre width will allow for four cages without overlap and an alley of about 0.9 metre. While a concrete floor makes cleaning easy, smooth hard soil is less expensive and quite satisfactory. A little loose sand or other litter spread on the soil before the manure collects will make manure removal easier. The building posts should be treated with wood preservative and be sturdy enough to support the cages. Rat guards should be installed on the posts at a height of 0.8 to 1 m. A central alley, raised 20cm and cast of concrete is easily cleaned and keeps manure from encroaching on the work area. Feeding and egg collecting are easily done by hand while watering may be either by hand or with an automatic system. It is important that the watering trough be carefully adjusted so that all birds receive water. The simplest method of supplying water automatically or by hand at one end is to slope the entire building and row of cages 10mm/3m of length.

The trough can then be attached parallel with the cages. Water must run the total length of the trough and it is inevitable that some will be wasted. Consequently a good water supply is essential.

Even though feed is distributed by hand, feed stores should be built convenient to each building to reduce carrying to a minimum. Eggs can be collected directly on to the "flats" that are stacked on a cart which is pushed down the alley. The cart can be made self-guiding by means of side rollers that follow along the edge of the feed troughs or the raised central alley.

Cage types that are equipped with pans to catch the manure are not advocated because they restrict ventilation. Previously used cages should be considered only if they are of a suitable design, and have been carefully inspected for condition prior to purchasing.

Figure 10.44 Cage compartment and various arrangements of cage tiers in open-side houses.

Table 10.14 Recommended Minimum Dimensions of Cages for Laying Hens

¹ Depending on the size of the breed

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