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Biosecurity in family flocks
I. Aini
Faculty of Veterinary Medicine, Universiti Putra Malaysia, 43400 UPM
Serdang, Selangor, Malaysia.
Biosecurity is a very important component of modern-day poultry management.
Success in disease control is very much related to how much biosecurity
procedures are implemented successfully and efficiently. How much biosecurity
is adequate for a particular farm depends on what the farmer wants to achieve,
which may vary from farm to farm, according to each farm’s cost-benefit
analysis. In family poultry production, some biosecurity measures can be
implemented in order to improve disease control and productivity. Any further
improvements would require cost-benefit assessments and the farmers’
willingness and capabilities to carry them out successfully.
Keywords: Biosecurity; family flocks; free-range and backyard poultry; semiintensive; family poultry
Introduction
In any poultry production system, the bottom line for the farmer is profitability.
Profitability can be in the form of high economic returns or cheap protein for the
family. For many family flocks in developing countries, the second output is the
more common reason for keeping poultry. Disease outbreaks or subclinical diseases
cost poultry producers and related industries millions of dollars a year in lost revenue.
Therefore, one of the most important factors linking with profitability in poultry
production is to ensure the best of health for the flock. To achieve this goal, good
hygiene and disinfecting practice play an increasingly vital role. In addition, usage of
vaccines, medicines and regular monitoring of flock health programmes have
contributed towards the establishment of flocks with a low disease incidence. To
maintain this favourable trend, a well organised hygiene and disinfection programme
should be established. Nowdays this type of programme in any livestock farming is
popularly known as BIOSECURITY. Biosecurity is considered as the key-word to
the success of today’s intensive poultry farming. It is the cheapest and most effective
means of disease control if applied properly. No disease prevention program will
work without it. This paper discusses how best biosecurity can be applied in family
poultry flocks.
Family poultry
Let us have a clearer picture of what is meant by family poultry production and how
they differ from commercial poultry, especially in terms of management. Family
poultry usually refers to smallholder poultry production which comprises of
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production under the free-range, backyard (which are traditional extensive husbandry
systems) and small scale semi-intensive systems. In most countries, the chickens
kept under these systems are either native or indigenous breeds and their crosses or
very seldom, the commercial chickens. Commercial poultry usually require high
external inputs and are less hardy than indigenous breeds, thus less preferred by small
farmers in rural areas. In the free-range system, chickens are usually let loose to
scavenge for food, with no or little shelter provided. Under the backyard system, the
management is very similar to the free-range system (sometimes free-range and
backyard systems are used interchangeably) except that farmers may provide fencing
to the area or sheds are provided for the chickens to return to at night. Some farmers
keep the chickens enclosed during the night under their houses, if the houses are built
on stilts. For the small scale semi-intensive system, the breeds kept are usually
crossbreds of indigenous chickens or the commercial breeds. Sheds are provided and
chickens have free access to areas outside the sheds but within the fenced area.
Though chickens dominate the family poultry production other species of poultry
such as ducks, turkeys, guinea fowl, pigeons, geese, swans and others are sometimes
included.
The free-range and backyard chickens usually scavenge for food which
consists of insects, worms, grasses and local weeds, table and kitchen leftovers,
fallen grains and others. Sometimes they may be supplemented with paddy, rice bran,
coconut cake, tapioca, corn, wheat or other local grains. Most of the chickens kept
under semi-intensive systems receive either home-mixed feed or commercial feed or
combination of commercial and other locally available feed resources.
As mentioned earlier, family poultry are usually kept for dual purposes (egg
and meat production) in order to obtain cheap protein supplement for the family.
Extra family income is more associated with chickens kept under small scale semiintensive system though chickens kept under backyard or free-range systems are also
sold when the farmers need extra cash. According to Sonaiya et al. (1999), besides
for family nutrition and income, family flocks are also kept as a symbol of wealth, to
be used for ceremonies, sacrifices, gifts and savings, as well as a barter system in
exchange for other livestocks or items. Sonaiya, et al. (1999) gave an excellent and
comprehensive review on family poultry, their importance and research options. In
general, family flocks form an integral part of households in rural areas and become a
very important component of those living in the rural areas.
Family poultry suffer losses not only from diseases caused by pathogenic
organisms, but also from predators (Aini, 1990; 1998; 1999). In most cases, control
of diseases is either lacking or very minimal, due to their unique management
systems. The most common diseases reported is Newcastle disease (Aini, 1990; Bell
and Mouloudi, 1988; Branckaert, 1996; Spradbrow, 1994; Ronohardjo, 1984;
Atienza, 1987; Supramaniam, 1988). Other major diseases identified include
infectious bursal disease (Fa, 1993) Marek’s disease, fowl typhoid, fowl cholera,
mycoplasmosis and coccidiosis (Adene, 1996; Aini, 1990). Other health problems
include those caused by endoparasites, ectoparasites and to a lesser extent,
microfilaria (Aini, 1990; Zaria et al, 1993; Amin-Babjee et al, 1998a, 1998b).
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Biosecurity
What is biosecurity? There are many definitions and reasons for biosecurity given by
various experts. However, in general, they are all concerned with the prevention of
disease from entering a poultry enterprise or spreading of the disease within the
farm. According to Marks( 1998), biosecurity is:

controlling the buildup of endemic biological agents. The buildup of these
agents will result in depressing productivity and performance, together
with background immunosuppressives.
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
prevention of highly contagious and potentially lethal organisms from
entering flocks. Pathogenic organisms entering a farm or spreading within
a farm will cause devastating effects on the flocks performance.

control of disease agents that are of public health concern.
There are two levels of biosecurity - at the international level and at the farm
level (Too, 2000). At the international level, biosecurity is towards prevention of
disease transmissions between countries. This is especially important if a country
exports or imports poultry. In some countries, family poultry producers cross
national borders freely with their birds (Sonaiya, 1999). Disease outbreaks therefore
easily spread across national borders. Disease control in this case, requires regional
efforts. At the farm level, as mentioned previously, biosecurity involves the
application of disease control measures to prevent the introduction of new infectious
diseases and to avoid them from spreading, either between farms or within farms.
Biosecurity is a package or set of practices which usually incorporates good
hygiene which is the basic principle involved in cleanliness. Rightfully, Marks
(1998) stressed the importance of cleanliness in controlling the buildup of harmful
organisms, which acts as an important prerequisite for effective sanitation.
Sanitation in turn is aimed at reducing biological loads in or on inputs into the
biological system. Biosecurity is therefore an attempt to attain good poultry health
without the massive administration of medicines. Under practical farming conditions,
it is impossible to eliminate pathogenic organisms from the housing, equipment and
the surrounding environment, but biosecurity can help towards reducing the challenge
of the pathogens below the threshold level that causes disease (Jordan, 1990). We
must remember that it is extremely difficult and expensive to clean and disinfect
poultry facilities once they have become contaminated with pathogens. Prevention is
therefore better than cure.
Many farmers, especially smallholder or family poultry farmers, often fail to
appreciate the importance of biosecurity. This is mainly due lack of understanding on
the concepts of flock diseases and the principles of disease control. As a result, they
(mainly the family poultry group) either neglect the preventive measures or
exaggerate the preventive measures (some commercial farmers), measures which are
difficult to implement and therefore ultimately become ineffective (Too, 2000).
For biosecurity to be effective at the expected level (which varies from farm
to farm), the farmers must be very clear about its objectives. The biosecurity
measures to be taken should also be practical for a particular farm. The most
important is, it should be sustainable and cost effective.
Biosecurity programme usually involves the following factors: farm design,
location, fencing, flock size, single age housing, introduction of new birds,
replacement stocks, quarantine of new acquisitions, movement of workers, visitors,
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vehicles, cleaning and disinfection, and disposal of dead birds. All these factors can
be grouped into three major components:
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
isolation - confinement of animals within a controlled area.

traffic control - includes both the human and vehicle traffics into the farm
and within the farm.

Sanitation - includes disinfection of materials, people, vehicles and
equipments entering the farm, and the cleanliness of the equipments and
personnel on the farm.
Isolation and traffic control are important since diseases can enter a farm via one of
the following routes:




human traffic, such as workers and visitors
introduction of new poultry
contaminated equipment or premises
vectors, such as rodents, wild birds, insects, wind, water, etc.
A sound biosecurity programme also includes appropriate vaccination
programmes, medication, the knowledge of diseases prevalent in the area, their
impact on performance, food safety issues and the risks of introduction (Marks,
1998).
At the village level, contacts between flocks of different households, the
exchange of birds as gifts or entrusting, the common practices of buying and selling
of chickens on farms or in local markets, are the important sources of disease
transmission. Similarly, other domestic fowls and wild birds form other sources of
infection. Can biosecurity be applied in family flocks, bearing in mind the different
management practices? Let us move through some of the biosecurity measures which
may be practical for family poutry flocks in reducing the level of disease problems.
Biosecurity in extensive and small-scale semi-intensive family flocks
When I mentioned the above topic to a colleague, his immediate reaction was “What
biosecurity? It is non-existent!”. However, when we pondered back into biosecurity
practices, we agreed that some of those practices may be applicable in free range
flocks, though with difficulties and may be with limited effectiveness. It is made
more difficult when infectious agents never lack the supply of susceptible flocks.
With free-range poultry, new chicks are hatched every now and then. They become
the constant supply of susceptible hosts. Though disease control is either very limited
or none at all, biosecurity is practised in most farms in some form or another, either
knowingly or not. Can we help to improve these biosecurity measures?
Location and farm/shed design
Ideally, a poultry farm should be located in a well isolated site away from other
farms. An incorrect choice of location of the farm can often impose problems in the
control of diseases. However, this is not always possible, especially with family
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flocks. For birds kept on free-range system, there is always contact among birds in
the neighbouring areas, indirect contacts with rodents, wild birds and others. Disease
transmission from one flock to another has no limit. In the case of birds kept under
backyard systems, where minimal housing or shelter is provided, they can still be in
contact with birds from the other households but the contact can be minimised
especially for the new hatches. This can help in terms of better survival rates for the
young chicks. Provision of sheds/housing can also control the entry of predators,
especially at night.
A small scale semi-intensive system, on the other hand, usually is associated
with provision of simple housing in an enclosed fenced area. Though the birds are
still free to roam around outside the sheds, they are limited by the fence. Besides
better prevention of the entry of predators, this physical barrier controls the contacts
with other birds in the neighbourhood. With the shed and fence, transmission of
infectious agents from movements of people and vehicles can also be reduced.
Bird proof poultry houses is another important feature in biosecurity, in order
to prevent the entry of wild birds, that may be potential carriers of diseases.
Depending on the type of materials used for the shed and the cost, sheds for the semiintensive system can incorporate this feature.
Another important aspect is the type of materials used for the houses or sheds.
In the rural areas, locally available wood or bamboo are usually used. They usually
become a good hiding place for external parasites, such as mites. Kerosene oil is
usually recommended to cover the wood or bamboo, to prevent the build up of these
ectoparasites. Some of these materials which have been infested with ectoparasites
should be replaced regularly, especially nesting materials.
Some farmers use baskets made of bamboo and other materials to raise newly
hatched chicks up to several weeks. These baskets should be cleaned and moved to
different areas regularly, to prevent build up of infectious agents, especially coccidia.
The place should also be kept dry so as not to provide favourable sporulation
conditions for the oocysts.
Single age group
The “all-in-all out” system as practised in intensive farming provides considerable
advantages in the disease control management. Proper sanitary practices can be
effectively carried out, coupled with the necessary resting period of the building to
ensure no infectious agent is carried over from one batch to another. Birds of
multiple ages kept on the same premise constitute a serious disease potential from
sick birds and recovered carriers, especially when birds of different ages are closely
associated together. Multiple age groups is the reality for free-range and backyard
family flocks, which poses an almost impossible task of good disease control. In this
kind of management, new birds are always being introduced into the flocks, either
due to new hatches, new purchases for replacements, or received as an exchange or
gifts. Quarantine is unheard of in this type of management. It is advisable for the
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farmer to keep these new additions separate from the others at least for one to two
weeks before they are let loose together with the old stock.
The single age group, “all-in-all-out” system can only be applied for the semiintensive system. The least that can be done is to ensure that a shed houses birds of
same age group, even if the farm consists of birds of different age groups.
Single species of family poultry
It is not an uncommon practice for family poultry farmers to keep several
species of birds together, especially for the free-range and backyard systems.
Chickens and ducks, chickens and turkeys, chickens and guinea fowl or combinations
of several of those species are a common practice. The obvious disadvantage is in
terms of disease control. One species that may be naturally resistant to a disease may
act as a carrier of that disease, transmitting it to another species which happens to be
very susceptible. Some diseases may be very mild in one species of poultry, but very
serious in another. It is therefore important to educate the farmers and to make them
aware that keeping only one species of birds in a farm is a better policy in terms of
disease control.
Disposal of dead birds
When birds die from infectious diseases, their carcasses become a source of infective
foci to other birds in contact with them. The carcasses can also be carried to other
areas or farms by dogs or other animals, transmitting the disease further. Therefore
dead birds should be removed and disposed quickly and properly, to ensure no
contact with other birds. In the rural areas, the easiest method of disposal would be
by burying. This would ensure that wild dogs or other animals will not be able to
move the carcasses to other places, and the infective foci is removed from the farm
site. Burning in a dug-up hole is another method of disposal commonly practised in
some villages.
Cleaning and disinfection
Effective cleaning and disinfection is an essential component of good hygiene and
thus one of the key biosecurity measures for disease control. Disinfectants are
usually ineffective on dirty surfaces. Cleaning cannot be associated with free-range
systems but a limited disinfection can be applied. A good example would the
application of lime to the compound after a disease outbreak, when all birds are
removed to another area or no longer available due to mortality. Where houses are
available for the backyard and semi-intensive system, cleaning and disinfection can
be carried out from time to time to reduce the build up of pathogenic organisms.
Suitable types of disinfectants can be selected based on cost and effectiveness. Lime
is usually the common choice among small farmers due to its low cost.
Vaccination and medication
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Regular vaccination programmes for endemic diseases are essential in all farms. The
farmers therefore should know which diseases are endemic and be aware of other
potential disease problems in their area. Vaccination programmes can be carried out
easily in birds kept under semi-intensive systems. However, the logistic problems are
encountered for birds kept under free range or backyard systems.
Newcastle disease, being the most common disease in family flocks, is the
most researched disease in native chickens. Thermostable vaccines (NDV4 and
NDI2) which can be applied onto feed have been successfully developed (Copland,
1987; Aini et al, 1990a, 1990b; Jagne et al, 1991; Spradbrow and Samuel, 1991;
Sapradbrow, 1993). A major concern at the moment is in the identification and usage
of local food carriers to introduce the vaccine. With further improvements, we hope
that these vaccines can be used with ease in free-range chickens.
Farmers’ awareness on the need of regular vaccination is essential to ensure
that vaccination is carried out in the farm. Together with other biosecurity
procedures, disease control can be better achieved.
We do not want to load the birds with medications which can be expensive
and may have limited success if the chickens are overloaded with infectious agents.
Thus, medication should be used with caution, especially in the free-range, backyard
and semi-intensive systems.
Biosecurity for the family
The other aspect to be considered when family members are very closely associated
with the poultry, is the impact of the flock on the health and hygiene of family
members. Farmers that keep the chickens or other poultry species under their houses
must ensure that the place is always dry and well ventilated. Failure to observe these
conditions will result in a very unhygienic situations together with the smell that
disturbs the family. Ectoparasites such as mites and lice from the poultry may result
in disturbing irritations, especially to young members of the family. In some
households, chickens are free to roam around in the house or sheds of the owners
resulting in the accumulation of fall-out feathers and faeces. Thus cleanliness should
always be practised by the farmers, especially before each meal.
Diseases such as aspergillosis, cryptococcosis (from pigeons), avian influenza
(from water fowl), and Newcastle disease have zoonotic potential, thus the farmers
should always be on the look-out. Hygienic practices should be able to keep these
diseases away from family members. Salmonella enteritidis infection is another
disease of public health importance. Some farmers who practise semi-intensive
systems have the tendency to overload chickens with antibiotics as an easy alternative
to biosecurity measures. In many developing countries, certain antibiotics are freely
available to farmers. This practice is of great concern to consumers, thus farmers
should be made aware of the negative effects of over utilisation of antibiotics as it
relates to antibiotic resistance in humans.
Dead birds should always be disposed of quickly and properly. This is not
only to remove the source of infective foci to poultry but also to family members.
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Conclusion
Nature has a vast reservoir of infectious agents which are just waiting to enter and
establish themselves in the right hosts. Even in the most modern, well managed
poultry farms, outbreaks of endemic diseases or introduction of new disease agents
are reported from time to time. This is usually attributed to the breakdowns in the
biosecurity measures. From time to time, the farmer should assess the biosecurity
steps practised on the farm to ensure that they are capable of meeting the level of
expectations for disease control. Farmers of family flocks face a more challenging
task of keeping their birds away from diseases. A limited biosecurity system can be
practised by these farmers. Though the success may be limited, whatever
improvements in terms of production and health of their flocks, resulting from
biosecurity measures, means a better nutrition and income for the family.
Acknowledgements
I would like to express my sincere gratitute to FAO for sponsoring my participation
at the 21st World’s Poultry Congress 2000, and Ms Normadiah Sukaimi for typing
the manuscript. My thanks are also for Dr. E.F. Gueye, Prof. E.B. Sonaiya and Dr.
Jonathan Bell for sharing their thoughts on the subject written.
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