What are the requirements of the extensive system?
1. Land: the land must be large, well-drained with trees for shade.
An external fence is required to restrict chicken from straying. 100 birds require 0.4 of hectare.
2. Runs (partitioned areas): the land should be partitioned to allow rotation. This reduces diseases and parasites.
3. House: the house is constructed to provide shelter and an area for laying nests. It should be easy to move form one run to another.
Advantages
These include:
Cannibalism and egg eating are reduced because the birds are not crowded and are free within the run.
No need to provide grit as birds picks it from the soil.
Less feed is used as birds pick insect and grass.
Manure is evenly spread to the runs, this helps vegetation to regenerate.
Birds are of good body size and stamina.
Disadvantages
These include:
A lot of land is needed which may not be available if you intend to keep a large number of birds;
Birds can be stolen or eaten by predators;
Eggs get lost in the runs;
Eggs get dirty.
2. Intensive Systems
In this system, the flocks are kept inside the house entirely with no access to the land outside. There are two types of intensive systems: the deep litter and battery system.
A. Deep Litter Systems
In this system, birds are kept in large pens and on floors covered with litters like straws or saw dust up to a depth of 8-12 inches. This system is suitable for producing fertile eggs when cocks and hens are kept together and for raising chicks and broilers, see Figure 2.4 below.
Figure 2.4: A deep litter housing system.
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Requirements for deep litter systems
1. Site: the site should be located in a well drained area;
2. House: the roof should be leak proof, made of aluminium sheets, corrugated iron sheets or asbestos. A grass-thatched roof is not good as it harbours pest and require frequent replacement.
3. Ventilation: the wall on the leeward side should be open from 60-90cm above the ground and covered with wire mesh. Good ventilation is important so as to reduce heat, humidity and harmful gases.
4. Floor: the floor is covered with litter, such as, saw dust, wood shaving, crushed maize cobs, and coffee and rice husks, chopped dry grass, etc. The litter should be turned regularly and more added as it becomes contaminated with droppings. Turning or stirring the litter encourages the multiplication of micro-organisms. These breaks down the hen’s dropping and eventually convert the litter into a mass of fine, dry, friable material which is normally odourless and comparatively hygienic. Turning is done either with the help of a fold, or by throwing grains regularly on the litter. As the chicken scratch for the grains, they turn the litter. When introducing new litter mix with a little of the old so as to introduce bacteria which help the litter to decompose. The depth of the litter should be kept between 15-30cm.
5. Feeders and waterers: these should be clean and well distributed to avoid overcrowding of birds and contamination of the feed and water.
6. Roosts: you should provide timber frames on which the bird perch for rest. You should allow 22.5cm – 30cm per bird and 1-1.2m high. The roosts should be moveable in order to avoid dampness caused by the accumulation of droppings in one spot.
7. Nests: are laying boxes: these should be large enough to make the birds comfortable. They should be built in a dark place in order to discourage egg eating and cannibalism. The floor of the nest should be covered with soft dry grass or wood shavings in order to prevent egg breakages.
There are two types of nests: the individual nests and the communal nests:
The individual nest accommodates one bird at a time. It measures 25-30cm wide, 30-35cm high & 30-36cm deep
The communal nest accommodates many birds at a time. Its door is 20x20cm.
Advantages of Deep Litter System
Many birds can be kept in a small area (high stocking rates);
Labour requirement is low as one person can care for many birds;
The system can be used to rear breeding stock;
Birds are safe from predators and thieves;
There is fast accumulation of manure;
Less loss of eggs as in free range;
Ammonia produced by decomposing organic matter in the litters acts as a disinfectant against coccodiosis.
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Disadvantages of Deep Litter System
Incidences of pecking, egg eating, cannibalism, feather plucking are high;
There is an accumulation of pests and pathogens in the litter. Dry litter causes respiratory problems;
It is difficult to know a poor layer as birds lay eggs in common nests;
Eggs may become dirty especially if laid on the floor;
Litter may be difficult to find in some areas.
B. Battery Cage System
In this system, birds are confined entirely in cages throughout their laying period, see figure 2.5.The cages are made of wire mesh. In each cage 1-3 birds are kept. The cages are arranged in rows which are then arranged in tiers, that is, a row is built over another. Cages have tiers varying from 3-6 in numbers with slanting floors to allow the eggs roll easily into the tray. The lowest tiers are normally 60-90cm above the floor. This height allows easy cleaning of the floor. The water troughs and feeder are fitted above the front side of the cages from one end of the row to the other. Eggs are collected from a tray behind the tiers. The cages are 45cm wide and at the front 45cm high and 57.5cm deep.
Figure 2.5: Battery cage system
We hope that your answer included the following causes of direct contamination:
touching infected skin, or
being in close contact with a person who is infected or who is sneezing, and/or coughing.
Advantages of Battery System
Higher egg production due to less energy wastage by birds;
Accurate egg records can be kept because it is easy to know which bird has laid;
Cannibalism and egg eating are minimized;
Eggs are clean because the hens do not step on them;
Less labour is needed especially where mechanization is practiced
It is easy to identify sick birds quickly;
Birds do not contaminate food and water thus there is no re-infection with worms and coccodiosis;
Culling or handling is easy as hens are restricted to a small place;
Broodiness is discouraged as the birds are not able to reach eggs;
A large number of birds can be kept in a small place;
There is greater efficiency in the control of diseases and parasites.
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Disadvantages of Battery System
A high initial capital is required in addition to the house;
It requires increased level of management;
In case of a disease outbreak, it can spread very fast;
Birds develop bruises on combs, breast and toes.
3. Semi Intensive System
The semi intensive system can be divided into two: the fold system and the house and run method.
A. The Fold system
In this system, birds are confined in small structures called an ark or fold. A fold unit measure 3.5m long by 1.5m wide and 1.5m high. This is enough to hold 10-15 hens.
One third of the fold is roofed to provide shelter. The rest of the fold is left open but it is enclosed with wire mesh. The unroofed part is used for sunning and exercise. The folds should be moved daily to a fresh ground to reduce build up of diseases, provide fresh grass, avoid accumulation of droppings and also to spread the manure. See figure 2.6 for an illustration of the fold system.
Figure 2.6: The fold system with wheels
Advantage of the fold system
Manure is spread uniformly in the field.
Less feed is used because the bird eat grass
This system reduces build-up of parasites and diseases.
Disadvantages of the fold system
Few birds are kept per fold. Where many birds are kept, many folds will be required and this is very expensive
It is labour intensive in that folds have to be moved from one place to the
