Biosecurity practices and farm hygiene are implemented on poultry farms to reduce the risk of disease agents moving on to farms from outside sources (eg wild bird populations or from other farms), the movement of disease agents between sheds on the same farm, carry over of disease agents from one batch to the next in the shed environment, and carry over of disease agents from breeding flocks to their progeny via the egg.
Farmers take a range of precautions to prevent entry of diseases onto broiler farms.
In common terms, a disease is an abnormal condition that is caused by infection, basic weaknesses, or environmental stress. A disease is defined by a specific group of signs or symptoms. Diseases prevent affected animals from functioning normally.
Health is the overall condition of an animal at a given time. Disease causes this condition to weaken. This can result in poor productivity and reduced quality of the affected animals. It could even lead to the death/loss of one or all of the birds in a flock.
Diseases can be categorized by common causes, such as genetic, mechanical, toxic, and nutritional. Infectious diseases are caused by viruses, bacteria, and fungi. Parasitic diseases are caused by protozoa, worms, and external parasites such as mites and lice.
Infectious agents, commonly referred to as “germs,” move from one susceptible bird to another in order to survive. For this to occur in a flock, a sufficient number of disease-causing agents must be able to gain access to the susceptible birds.
These are birds that have no immunity or other resistance against these agents or whose defense mechanisms have been reduced or overwhelmed at the time of infection.
Why is Disease such a Concern in Poultry?
Certain diseases have the potential to decimate a region’s poultry industry. When one of these diseases strikes, a quarantine or embargo could suddenly be placed on a region or nation.
This could cause widespread economic hardship for both commercial and small flock owners.
To protect their animals and the poultry industry flock owners must be able to identify diseases quickly to prevent them from spreading to other animals. The sooner a disease is identified and action is taken, the better.
How are Diseases Spread?
Diseases are spread by:
Direct contact (bird-to-bird, infected manure)
Indirect contact (contaminated equipment, people, environment)
Vectors (wild animals, rodents, insects)
In addition, infectious agents need a “home base,” or reservoir of the disease, to persist in an area. This reservoir could be other birds or organic matter providing life support for these agents. Disrupting the methods by which diseases are spread can greatly reduce the threat to your flock.
Sources of Disease
Humans, whether as visitors, neighbors or farm workers, can be a major source of disease transmission. Carriers can include employees who work on several poultry farms and equipment that moves between farms.
Poultry brought to the farm can carry infectious diseases. Day-old chicks or poults, pet birds, replacement pullets, cull- or sickpen birds, or birds of different ages or species are all possible sources of contamination. Wild birds may carry and transmit diseases to commercial poultry flocks. Certain diseases, such as salmonella and coliforms, may be transmitted from the dam to the offspring through the egg.
Poor sanitation also can cause disease problems. Once a site is contaminated, carryover from previously infected flocks may become a reoccurring problem.
Disease outbreaks are influenced by the general condition of the flock. Conditions caused by poor management can reduce the flock’s resistance to infection.
Disease Control and Prevention on Poultry Farms
Good hygiene, sanitation and medication are important aspects of poultry farming or poultry keeping. To control diseases in the farm, poultry farmers must do the following:
- Rear chicks in isolation
- Avoid mixing birds of different ages together
- Screen out rodents and wild animals
- Keep visitors out of the poultry houses
- Secure an accurate diagnosis immediately trouble appears
- Vaccinate birds against diseases and where applicable, use a worming program.
- Avoid management stresses
- Dispose of dead birds promptly by burning or burying deep in the ground.
To prevent an outbreak of diseases in your farm, poultry farmers must observe the following instructions below:
- The poultry houses should be properly disinfected 2weeks before the arrival of chicks.
- Enough brooding equipment’s, feeders and drinkers must be provided.
- Give vitamins (anti-stress) before and after vaccination, medication, debeaking and transportation.
- Avoid spilling of water on the litter and always remove used litter fortnightly
- Deworm birds especially growers on litter monthly.
- Repeat Newcastle disease vaccine (Lasota) every 2-3months for laying birds.
- Give anti chronic respiratory disease (C.R.D) occasionally for 1-5days to birds before laying commences.
- Use growth promoters such as RE-OSAL tablets, 3NITROW and PITUDIZ for broilers from 3½ weeks and cockerels from 8weeks onward.
- Remove all noticed sick birds to avoid the spread of diseases.
Poultry Farming Disease Prevention and Management
Routine preventative measures form the next line of defence against disease, after providing a clean and hygienic environment through good poultry farming practices. Preventative measures include:
- parasite control
- identifying and treating sick birds
- separating multi-age flocks
- practising routine biosecurity procedures between flocks and staff working with them.
Poultry Farming Vaccination
Vaccination can prevent many poultry diseases. Follow a suitable vaccination program or only buy appropriately vaccinated stock. You can request vaccination certificates from your supplier when purchasing chicks or pullets.
Poultry vaccinations include:
- avian encephalomyelitis
- chicken anaemia
- egg drop syndrome 76 (EDS 76)
- fowl cholera
- fowl pox
- infectious bronchitis
- infectious bursal disease
- infectious coryza
- infectious laryngotracheitis
- Marek’s disease
- Newcastle disease.
For breeders of poultry, when vaccinating:
- always follow the instructions on the label, including storage conditions
- use disposable syringes and needles
- discard all unused vaccines, syringes and needles in a proper manner
- be clean, but never use detergents or disinfectants near vaccination equipment. Do not disinfect skin before vaccinating with fowl pox or Marek’s HVT vaccine, as this will kill the vaccine virus.
Check with your vaccine supplier or veterinarian for vaccine availability. Poultry Hub has more information about vaccination types, procedures and handling.
Birds that are housed on the floor and have access to pastures and outdoor areas will have greater exposure to internal and external parasites.
For birds housed in these conditions, it is important to have a prevention program in place and treat as required.
This helps to minimise physical stress and keep birds in good condition so they can resist disease. Control parasites by:
- regularly inspecting birds for external parasites
- spraying or dusting birds thoroughly with an approved insecticide if you can see lice or mites – spray the shed, perches and nests thoroughly, making sure the insecticide gets into crevices
- cleaning sheds and rotating ranges to prevent worms
- regularly checking faecal material for any sign of worms
- always checking the label on worming treatments for withholding periods as some are not suitable for production birds
- consulting a veterinarian.
Remove sick birds
Regularly observe your birds for any signs of ill health or problems within the flock such as feather pecking. Remove sick chickens and other poultry from the main flock and obtain a diagnosis from a qualified person.
Sick birds usually appear different to healthy birds. You can give the correct treatment once you identify the disease or problem. Keep ill birds quarantined from the flock until completely recovered. If medication is given, it is important to adhere to any withholding periods.
When introducing younger birds into a flock of older birds, there is an increased risk of disease transfer from the older birds to the younger birds. Older birds often build resilience to diseases and disorders that younger birds have not been exposed to.
There may also be an increased risk of feather pecking and social issues when introducing new birds to a flock.
It is preferable from a disease perspective to run single-aged flocks. However if this is not possible and you are running multi-age flocks:
- keep age groups separate – have an all-in and all-out system for each age group to allow for a complete clean and disinfection of facilities and equipment between batches
- always start work with younger poultry and finish with the oldest.