7. HEALTH AND DISEASE PREVENTION
Chickens are fragile and can get sick very easily especially when young
There are two major sources of disease.
Diet if not correctly formulated can result in the bird getting a metabolic disease due to a nutrient deficiency (vitamins or minerals) in the diet
Other diseases are caused by minute organisms called bacteria and viruses. It is often necessary to treat the chicks as soon as they hatch with a vaccine which allows them to resist the disease if it occurs. This is normally done at the hatchery. Newcastle disease is present in many countries and chickens need to be vaccinated more than once (see section 7.1)
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Remember that “prevention is better than cure!”
Many diseases can be prevented by keeping your poultry house very clean
Overcrowding of birds can cause disease
Do not allow other poultry on to your farm (e.g. neighbour’s scavenging chickens)
Do not allow other poultry farmers to enter your shed
Place a foot bath with a disinfectant in it or limestone outside the door of your poultry house
Have a special pair of boots/shoes that you will use only when you are working in your poultry house
Leave sufficient time between batches of birds to clean the house and get rid of diseases that need to have a bird (host) to survive
Remove old litter, dirty bags and contaminated rubbish and dump them far away but in a responsible place that will not contaminate the environment
Discard damp, old feed. It can grow mould which can produce toxins. They can kill or make your chickens sick
All in-all out systems in which all birds are the same age help to reduce disease out breaks
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External parasites such as mites, lice and fleas can make your poultry feel uncomfortable. This will affect their growth rate and egg production
Insecticides are used to treat the infected birds. A dust bath will also help to reduce these external parasites
Internal parasites such as different worms and minute protozoa causing coccidiosis can be prevented by medication
This is done routinely by adding a coccidiostat to the mixed feed for broilers
Remove immediately sick birds and bury dead birds.
Never eat or sell sick birds; they will make your family and others ill
7.1 Newcastle disease
There are two diseases that are particularly dangerous in many low-income countries. Newcastle disease (ND) is endemic (always there) in many countries and becomes active particularly at the start of the wet season. It can wipe out entire village flocks although a few individual birds often do survive. There are now ND vaccines that will withstand the heat for a short period (thermostable) of time. Vaccination is most effective by eye drop and birds should be vaccinated a month before expected outbreaks by a trained person. There is also a need to treat the birds at intervals through out their life. This is a specialised area and the poultry keeper will need help from experts but it is well worth the effort and the vaccine is not expensive.
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7.2 Avian influenza
The H5N1 strain of highly pathogenic avian influenza (bird ’flu) is particularly dangerous not only because it can infect different poultry species and wild birds but it can also kill humans. Village poultry are especially at risk because they are outside and may be in contact with wild birds and other poultry species (ducks, geese). The disease spreads rapidly through the poultry flock.
The virus can be spread by eating infected birds and can kill the consumer particularly if she/he is young. Household poultry keepers should keep themselves informed about the situation in relation to bird ‘flu as it often appears at particular times in the year.
We will now discuss the two specialised areas of commercial (intensive) poultry production: broiler (meat) production first and then egg production.
[END OF UNIT III]
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UNIT IV
8. COMMERCIAL BROILER MEAT PRODUCTION
Chicken meat is very popular throughout the world. It is seen as a healthy meat low in fat and rich in protein (lean meat). It is a meal for a family so you don’t need a refrigerator
To prepare for the chicks’ arrival it is best that you have a time plan or schedule
the house will be thoroughly cleaned and disinfected
shavings or litter on the floor
the brooder surrounds in place
the brooder heater checked and adjusted (if there is one)
feeders and drinkers in place. Chicks usually look for water first.
a supply of a small amount of starter feed is scattered on paper on the floor of the brooder so that the chicks can start to eat
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For the first 7-10 days the chicks will be brooded (see section 5.) Broiler chickens can grow very fast but only when well looked after and given good feed
After 3 weeks of age when the house temperature is less than 28–30 oC they grow best. In the tropics, the temperature is normally above 30 oC in the day time so they will grow a bit slower than usual
Some chickens will die in the first week particularly those that are small and weak. You must remove and bury them immediately
You can expect to lose at least 4 - 5 chicks out of 100 in the first 3 weeks. Another 2 may die later. Mortality can be much higher especially if management and housing conditions are poor. Some broilers, as they get older, may become lame and are unable to walk and get to the feeders. This is partly a breeding problem but may be reduced by slowing growth in the second week for about a week by limiting feed intake.
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Ideally, chicks should be given a bought formulated diet. A commercial starter diet should be purchased and fed for at least the first 10 days because they need to get off to a good start
They will have eaten only about 250 g of feed during this time. This will cost you less than 25 ¢/bird
A grower diet will then be introduced by mixing what remains of the starter diet with the same amount of the grower diet. This will mean that they can adjust easily to the new feed
When the mixture is finished, chicks will be on the grower feed only
Check chicks several times a day to see that they are comfortable and have feed and water
Check your chickens frequently. They do not like it too warm.
It will be helpful if you have weighing scales so that you can weigh feed given to the chickens and get the live weight of a sample of 10 birds every 2 weeks caught with a simple leg catcher. This will tell you how well your chickens are performing
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Do your birds reach targets at 3 weeks and 6-7 weeks? This should be your marketing age range for best growth and feed consumption?
Weight gain is weight of bird divided by age in days then divided by the total number of birds to obtain the average weight gain of one bird
Feed efficiency is feed consumed (kg) during a fixed number of days divided by the total weight of all birds (kg) consuming that amount of feed
As a guide, the average weight of your chickens at 6 weeks should be 1600 g and at 7 weeks 1750 g
Feed efficiency should be under 2.5 kg feed for 1 kg of weight gain at 7 weeks of age [a worked example of these calculation is given at the back of the manual]
Although your chickens look healthy you must still inspect them several times a day. You do not want to lose any. They are now becoming valuable and attractive to a thief
8.1 Marketing
Selling your chickens profitably is essential. You can sell them
alive on a bird or on a weight basis
through a middle man who will take some of your profit for himself
dressed, plucked, eviscerated (guts) and organs (lungs, liver, heart) removed. This is time-consuming
sell to an abattoir for processing
In some regions you will not have all of these choices
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8.2 Manure
Chicken litter will produce very valuable manure rich in nutrients
You can:
use it on your garden
make it into a compost
sell it
You are encouraged to grow your own vegetables and fruits as they are important for your family and cheap. Manure not only provides plant nutrients but importantly organic matter for the soil, This allows the soil to breathe
8.3 Record keeping
It is essential that you keep good records of feed used, dead birds, weight of birds at the end. These records will then be used to determine if you made a profit or a loss.
[A broiler record sheet is given at the end of this manual. The trainer will work through an example with you]
Little mention has been made here of vaccination of chicks. This is normally done at the hatchery.
[END OF UNIT IV]
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UNIT V
9. COMMERCIAL EGG PRODUCTION
There are several choices of how you house your hens for egg production:
in group battery cages (expensive but saves floor space)
indoors on the floor (barn hens or deep litter)
free-range out-of-doors during the day
large groups or colony cages indoors (see later)
For replacement or point-of-lay pullets (young hens not yet in lay) there are two options
the farmer can purchase hybrids or pure bred chicks from a hatchery (expensive) or
the farmer can hatch and raise his own chicks
9.1 Hatching chicks
The farmer:
can have a flock of breeder hens with one rooster for about 8 hens.
will need nest boxes with litter and placed in a secure, dry place
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will store the fertile eggs in a cool place for no more than 8 days
will allow a broody hen to incubate the eggs or your own small incubator (expensive and needs a reliable power supply although there are kerosene or paraffin heated incubators. (See section 9.2)
water and feed should be placed close to the broody hen in an isolated place
the nest should have a 2 cm layer of sand then 2 - 3 cm of litter on top at day 21 eggs will hatch out
Half will be females. The farmer must decide what to do with the males. They will grow much slower than broiler chickens but can be given a lower - quality feed than broilers after 3 - 4 weeks of age. It still may not be profitable to grow and sell them. Mother and chicks must be kept separate from the main flock of adult hens until about 4-5 weeks old.
9.2 Artificial incubation
A reliable power supply is essential for satisfactory egg incubation. A thermostat is needed to control the temperature at 39.5 oC and the relative humidity needs to be > 50%. Small-scale poultry breeders have successfully built small incubators to hatch 50 - 100 fertile eggs. A light bulb (s), controlled by a thermostat, provides heat although heating coils are also used. A tray of water on the floor of the brooder keeps the humidity above 50%. The eggs are turned 3 - 4 times a day. Ideally this should be done by marking the egg so that one complete turn is achieved each day but the eggs should not be rotated end to end.
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A homemade incubator
Paraffin or kerosene incubators used to be common many years ago. Heating is provided by a burning wick in a lamp similar to a conventional kerosene lamp for lighting purposes. The warm air is flowing constantly into and out of the incubator chamber. A damper controls the amount of warm air that enters or escapes from the chamber to outside is set manually once the temperature has stabalised at 39.5 oC at egg level so there is always need for an accurate thermometer.
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9.3 Pullets
They are usually raised indoors in the same way as broilers. They grow slowly and may need brooding until 4-6 weeks old. They are then given more space than broiler chickens. If there is an out doors fenced area, they can go there during the day.
They should be given 500 g of broiler starter feed for the first 4-6 weeks. When this feed is used up it is replaced with a lower-quality pullet-rearing diet until 17 weeks of age. They are then given a layer diet which is high in calcium (3%) and phosphorous (0.5%). This is needed so that they can lay eggs with hard shells. Pullets will now be transferred to their layer house as they will shortly come into lay.
9.4 Battery cages
can hold 1-5 hens per cage (50 x 40 cm x 45 cm high for each hen)
are expensive but can be made from local material
hens may peck one another and may need to have their beaks trimmed (a specialized job)
can scratch one another if claws are long with loss of feathers from the back
must be given a high-quality layer diet
will lay more eggs and eat less feed than hens in any other housed system
may be in future welfare issues as birds have little space. This worries the public
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9.4.1 Small scale semi-commercial cage unit
This is designed for a household wanting to keep only a few hens and have eggs for their family and to sell
a single cage unit of 3 compartments holding 12 layers. See trainer’s manual (10.3.1)
cage on legs or on a stand or legs constructed cheaply from bamboo
can be moved easily out of rain and bad weather to a safe place
thatched roof or without a roof if kept under cover
bamboo feeders and home-made drinkers (see illustrations 4.1, 4.2)
hens must receive high-quality feed to lay 9 - 10 eggs /day
system sustainable if 5 eggs sold and 4 - 5 eggs consumed by the household
money from egg sales is used to buy more feed
hens sold after 12 months for eating or force moulted (see section 9.7 )
money from egg and hen sales used to buy replacement birds or layer chicks and grown to pullets but starting these 20 weeks before selling old hens
9.5 Barn hens
