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The basics of chicken farming (in the tropics) Part 2 of 4

By goGreen | November 21, 2011
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Long water trough
Here water is supplied in two different ways:

a standing water
There is an adjustable float valve. When the water level in the trough drops, the float opens automatically. At the other end of the trough there is an overflow in case something goes wrong.

b running water
The water flow never stops and is constant; it does not react on an increased water consumption of  the birds. This type of drinker is used for all types of chickens, also on batteries. Different materials can be used:

V-form plastic or metal
easy to clean by the birds

U-form metal
much more water in the trough, at the same level; difficult to clean

O-form bamboo
difficult to clean; trough joints difficult to seal 6 leakage


plastic: very suitable for batteries, because it is not heavy;
sturdy, strong;
support every two metres
trough parts not longer than four metres and coupled with expansion coupling
metal:  galvanized iron, aluminium, stainless steel (only galvanized iron is interesting because of its price);
parts not too long (approx. 4 m) and couplings sealed with kit;
paint the inside for longer life

bamboo: if too small, the birds will not drink!
treat the inside for longer life

Because long water troughs can be really long (100 metres!) they should be strictly level otherwise  there is a problem with the water. The most stable situation is suspending the trough from the roof (rafters or trusses) with chain for metal cables, not too far from each other (about 2.5 metres). To prevent the chickens from sitting/resting on top of the trough, very often a wire is fixed approx. 7.5-10 cm above the trough.

With the standing water system, having a separate water tank is strongly recommended, for two reasons:

1 to eliminate pressure fluctuations (if these occur)
2 the tank can be used for mixing drugs with the drinking water

but the consequence is a higher water temperature.
With a running water system, water comes straight from the mains and is therefore cooler (if the water passes underground).

In general, when there is a reliable mains, with relatively cool water, the running system is to be preferred.

Cleaning a long trough is relatively easy. There are two ways to do it:

Plastic hanging drinker
The plastic hanging drinker has a valve built in the drinker body. There are two main types: with or without ballast tank on the drinker. The one without ballast, however, is very unstable (water losses!) and for that reason most hanging drinkers are fitted with a ballast tank (filled with water, sand or pebbles).

The drinker itself is made of plastic (excluding two springs inside the valve unit). It has a bell-trough and a valve unit. The bell-trough may have one or two rims. Nowadays the one with two rims is hardly used any more because it is difficult to clean. The one-rim type may be dangerous for day-old chicks (drowning!) because of its relatively large size. The ballast tank should be of good quality otherwise the drinker may easily start leaking. The weight in the ballast tank is normally about 1.5 kg (= 1.5 litre of water).

The valve is the most important part of the drinker. There are two possibilities:

1 the water level in the bell-trough is regulated by the weight of the water in the trough plus the weight of the ballast. If the weight of the ballast diminishes (trough water evaporation), the valve reacts by putting more water in the bell-trough, to point of overflowing (wet litter and manure!);

2 the weight of the ballast does not act on the valve. Only the weight of the water in the bell-trough is decisive for the functioning of the valve.

The hanging drinker system is a low-pressure system. There is a water tank (connected with mains or otherwise filled with water) and from the tank the water flows through the main pipe to the drinkers. The water tubes of the drinkers are connected with the main pipe by means of T-piece or saddle connecters. The pressure on the valves must be 0.3-0.5 at. corresponding with a difference in height between the valves and the water level in the tank of 3-5 metres (every metre is 0.1 at. pressure difference).

The end of the main pipe must be open, to allow possible air bubbles in the system to escape without troubling the water supply to the birds.

The positive points of this hanging drinker system are:


Nipple drinkers
Nipple drinkers are mainly used in laying cages. In temperate climates almost 100% of the batteries are fitted with nipple drinkers. For hot climates the advantages of nipple drinkers are less distinct. A nipple drinker in itself is a very simple piece of equipment. Although there are several types, all nipples have three main parts, namely nipple body, nipple pin and nipple top dolly. The body can be made entirely from stainless steel or the inner body only. Nowadays the colour of the body is always red as it is believed that the red colour has a certain attraction for the birds. The nipple pin is the important part because it must be lifted by the birds, to open the water supply. The weight of the pin plays an important role: too heavy, it is difficult for the birds to lift the pin; too light, the nipple may leak.

The nipple top dolly makes the nipple return to its closed position. Nowadays nipple drinkers have a fixed top dolly, to prevent the dolly from falling off the nipple.

The best place for the nipple drinkers is in a side wall back in the cage. This position has certain advantages:

The water pressure on the nipples must be very low. Under normal operation the bottom of the water tank is on the same level as the nipple water pipe. If the pressure rises, the nipple starts leaking (wet manure).

Sometimes leaking is necessary in order to avoid watering problems with newly-placed birds which have to get used to their watering system. Nipples start leaking when the water pressure is increased or/and the nipple water pipe is turned.

As with the hanging drinker, the end of the nipple water pipe should be open, above the water level in the tank.

For proper functioning of the nipple drinker system it is not only necessary to have good quality, clean drinking water and a good quality nipple, but also:

2.8 Laying nests
Laying nests are indispensable for layers that are not housed in batteries. In non-battery houses floor eggs are a problem all over the world. What one can do to cope with the floor egg problem:

Types of laying nests

a Individual nests
With litter; manual/automatic egg collection.
Without litter; the wire bottom of the nests slopes forward to the egg cradle (so-called roll-away laying nests).

Size of individual nests:   width 25-30 cm
depth 35 cm
litter retainer about 15 cm
Capacity: 4-5 layers per nest

Perches are necessary for the hens to enter the nest. Removable nest bottoms make the cleaning much easier. With roll-away laying nests the slope in the bottom should be 14%; use wire with a mesh of about 1 cm.

2 Communal laying nests
Sizes e.g.length 2 metres, depth 0.7 metre. Capacity per square metre 50-60 layers. Use litter with a depth of 15-20 cm so that the eggs can ‘sink’ into the litter. Ventilation inside the communal laying nest is very important. Communal laying nests are not suitable in tropical conditions.

The following illustrations and other illustrations in this chapter were provided by IPC Livestock Barneveld College, from lecture notes prepared by J.A.Hulzebosch of that College.

3 The feeding of chickens

Chickens need food for:

3.1 The composition of chicken feed

Carbohydrates (and fats) provide energy to the bird. Especially the starch of cereals and roots is important in chicken feeds as supplier of energy. In most countries cereals make up the main feedstuff ingredient for chickens. In general, grain products are from a practical point of view poor in calcium and rich in phosphorus.

Fats have a high energy value (fats are ‘energy-rich’ as we all know). Sometimes extra fats are added to broiler rations, to improve the food conversion rate.
The fat content in cereals is low but maize grain has a relatively high fat content. Yellow maize turns the skin and fat of chickens yellow and colours the egg yolk.

Crude protein
Unlike ruminant animals, chickens need high-quality protein in their ration, because chickens cannot make amino-acids themselves. Protein is made up of about 20 different amino-acids. Of these acids about 10 should always be present in poultry feed, in sufficient quantities and in the right proportions. Three amino-acids are likely to be lacking in (natural) chicken feed, namely lysine, methionine and cystine. For that reason feed millers make a special effort to guarantee that they are present in their chicken feed formulations. Lysine is abundantly present in feedstuffs of animal origin and in soybean cake. Methionine can replace cystine, but not the reverse. Methionine is produced industrially and as such
is used in chicken feed formulations.

Crude fibre
Unlike ruminants, chickens can hardly digest crude fibre and it should not be present in excess in chicken feeds. Chickens only utilize part of the crude fibre in the ration. Only the crude fibre which arrives in the blind guts is digested, with the help of bacteria. This is about 10% of the feed. Nevertheless, crude fibre in the ration is important because it stimulates the intestinal wall to greater activity.

Inorganic matter (minerals)
Only Ca and P are mentioned here (other elements are also needed). Calcium and phosphorus have the following functions:

The egg shell is made up of calcium carbonate for about 90%. Apart from this Ca and P are needed for the formation of egg content.

A laying hen needs about 3.7 g Ca per day. Generally speaking in the tropics, with relatively low feed intakes, to be on the safe side the Ca content of the feed of laying hens should be about 4% (assuming that the feed intake is 100 g).

Other components
The ingredients used for chicken feed normally already contain some vitamins. But often the vitamin content is insufficient and extra vitamins are then added by the feed miller. Apart from vitamins other substances may be added; the most important additives are:

Digestibility and energy content

What the chickens eat is not completely digested; part of the feed can be found in the droppings. The more digestible a feed (ingredient) is, the less can be found in the droppings. Hence the term ‘digestibility’ and digestibility coefficient.

Starch and sugars (cereals, roots, tubers, sugar products and fruit) are highly digestible for chickens. But bananas form an exception to this rule. Fats and oils from lard, coconut and oil palm are less digestible than oils from groundnut, cottonseed, soya and maize grain. The  protein of legume seeds and seed cakes quite often needs heat treatment to make it digestible
and/or suitable for poultry. The heat treatment should be done with precision (neither too little nor too much heat). For instance, soybean seeds and cakes should be heat-treated to make them suitable for poultry feed.

In Europe and the USA soybean cake is by far the most important cake in poultry feeding (about 95%), because of its price, richness in indispensable amino-acids (lysine!) and its relative freedom from toxic substances. The best soybean cake contains about 50% crude protein, 2% fat and 3% crude fibre.

Energy content
In most countries the metabolizable energy content of a feedstuff is used to measure the value of a poultry ration as far as energy is concerned.  The unit of ME used to be the kcal; nowadays the unit MJ (Mega Joule) is mostly used; 1 MJ equalizes 240 kcal. In order to be able to calculate the ME of a feed, one should know the digestibility coefficient (for
chickens in our case) and the ME factor of the various components that make up the feed. The ME of a normal chicken feed ranges from 2500-3200 kcal/kg

Energy/protein ratio in feeds
As the chicken grows, relatively less protein is required in the feed; ‘starter’ feed should contain more protein than the feed for adult birds.

3.2 Mixing feed
Most chicken feed mixtures contain the following ingredients:
carbohydrates – mainly grains and grain by-products
proteins – oilseed cakes and beans, fish meal, meat meal
minerals – sea shell, limestone powder, bone meal sometimes trace elements are included in a premix

vitamins – e.g. lucerne meal and premixes; usually in small quantities
medicines – sometimes medicines are added to the feed
The mixing of these ingredients should be done very carefully because a chicken eats only a small amount of food each day. But this small quantity (only a few tablespoons) should contain all the ingredients the chicken needs, in correct proportion.

The ingredients used:

The most common types of mixtures are:

Mixtures are made up according to:

Mixing procedures (on the farm):

But a good check is always: a) there should be no colour differences in the mixture and b) it should not be possible to recognize the individual ingredients any more. Store the mixed feed in containers or clean sacks.

Pre-mixing vitamins and other small amounts
It is advisable to pre-mix small amounts of ingredients such as vitamins, trace elements and medicines, with one of the other ingredients.
Follow this procedure:

3.3 Grinding and pelleting
The grinding of certain ingredients on the farm itself may be necessary or attractive for certain reasons (for instance, in the case of farm-produced maize).

In general, grinding gives better digestibility. It should be done according to the type of feed to be mixed; adult chickens like feed particles of about 6 mm size, young chicks need a smaller-sized particle. Chickens never like dust (material that is too finely ground). All feed particles should preferably have the same size, otherwise the chickens will select certain
sizes, which may lead to an unbalanced ration.

Grinding is usually done by a machine; the ‘hammermill’ is the most common one. In the hammermill a number of metal parts rotate with considerable speed. They crush the feed particles until they can ‘escape’ through a number of sieves with a preset gauge.

Operating a hammermill

Sometimes feed is pelleted after it has been mixed. Pellets are small cubes varying in size. The feed is mixed with molasses and/or a chemical (for instance bentonite) for binding purposes and heated with steam. It is then pressed through a number of preset gauges and rapidly cooled down. The steam may also kill bacteria, which is desirable. Pellets reduce losses due to the blowing away of the finer particles (dust) and losses during storage. Less feed is wasted during consumption because  chickens cannot select between pellets and each pellet is a complete mixture.
3.4 Feed intake and feed conversion rate
Factors affecting feed consumption (in order of importance):

If there are no feed restrictions the birds will adjust their consumption according to their energy needs, so the higher the energy level the less they eat.

The temperature in the house has a particular influence on the chickens:

Thus the nutrient density of the feed should be increased to cope with hot weather. Another effect of hot weather is that egg weight decreases and that the egg shells become thinner.
When birds have free choice of feed, they tend to select the most attractive and tasteful parts (particles) first.

There are several ways to supply feed to chickens: by hand, mechanically, free or restricted, depending on the kind of management that is applied. But always try to prevent wastage. Most methods to reduce wastage require extra labour or equipment but are normally well worthwhile.

‘Restricted’ feeding stimulates the chickens to finish the feed so that no old stale feed stays in the feeder that affects the quality of the fresh feed. But ‘unlimited’ feeding (at pleasure, ad libitum) is still recommended when maximum growth is sought (day-old chicks and broilers).

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