If infected or infested with parasites, even the finest fed and housed cattle with the highest genetic potential will not develop and produce efficiently. As a result, excellent poultry health management is a crucial part of the poultry production process. Because of the high stocking densities of commercially kept chickens, infectious disease-causing agents can swiftly spread across a flock.
To be effective, poultry health management must prioritize preventing the spread of disease and parasites, recognizing disease or parasites early, and treating all flocks that are diseased or infested with parasites as soon as possible and before they develop into a serious condition or spread to other flocks. To do so, you’ll need to know how to spot infected birds, what steps to take to avoid or minimize disease, and how to keep an eye out for signals that the preventative program is working.
Health management principles
The following are the basic principles of poultry health management:
- Disease prevention
- Early illness detection is crucial.
- Disease therapy should begin as soon as possible.
Disease should be avoided as much as possible. Preventing illness is easier and less expensive than treating it. However, it is unrealistic to believe that all diseases can be avoided. Some may inevitably get past the defenses; in which case the condition must be identified as soon as so that treatment or other appropriate action can be taken to bring the situation under control and prevent harm to the flock.
Disease
Any condition that interferes with the proper functioning of cells, tissues, organs, and entire bodily systems is referred to as a disease. Poultry diseases are caused by a variety of factors, including:
- Essential nutritional deficiencies, such as vitamin, mineral, or other nutrient deficiencies.
- Toxic chemicals, such as poisons, are consumed.
- Physical harm, such as injury and exposure to extremes of the environment.
- Infestations of internal and external parasites, such as lice and worms.
- Microorganisms such as bacteria and viruses cause infectious illnesses.
Non-infectious illnesses are those that are caused by dietary shortages, toxic drug ingestion, or physical injury. Individuals must have a shared experience to develop these non-infectious diseases, and these diseases cannot be spread from bird to bird. Infectious illnesses are caused by microorganisms such as parasites, fungus, protozoa, bacteria, pneumonia, chlamydia, and viruses in the broadest sense. These illnesses are sometimes referred to as infectious diseases because they can be transmitted directly or indirectly from one bird to another.
Direct transmission happens when a sick bird conveys the disease’s cause to a vulnerable healthy bird through direct contact. The egg or sperm may be transmitted horizontally (from one bird to another) or vertically (from parent to offspring) via the egg or sperm within or on the shell. Indirect transmission occurs when the causative organism is conveyed from one bird to another by an intermediary host such as insects, earthworms, snails, or slugs, wild birds or animals, or another object such as equipment, food, or water, cars, humans, respiratory droplets, litter, or excrement.
Infectious illness causes
Pathogens or disease vectors are organisms or germs that can cause harm, such as illness in animals.
Many different infections can be conveyed from one bird to another or from one flock to another through a variety of methods.
These pathogens include the following:
- Viruses
- Bacteria
- Fungi
- Protozoa
- Internal parasites
- External parasites
Viruses
Viruses are the tiniest pathogens, only visible under an electron microscope. Viruses have an exterior layer/s of unique protein material around them, which is comparable to the genetic material of the cells they infect. Only inside the animal cell can they proliferate and cause harm, and if they infect and destroy enough cells, the animal will display indications of illness.
Antibiotics and other treatments, in general, have little effect on viruses, therefore few pharmaceuticals can cure viral disorders, however, there are situations when a drug can be used to reduce secondary infections. Quarantine and proper cleanliness to reduce the challenge, and vaccination to maximize the birds’ immunity to future threats, are the best ways to control infections caused by viruses. Some species may live for lengthy periods in bird dander and feather waste, trash and dung, insects, and rodents.
Bacteria
Bacteria are single-celled creatures with a nucleus that reproduce by simple fission, in which one cell divides into two, and some may do so extremely fast within the host or in a suitable environment. Some are extremely delicate and do not live outside of the host for extended periods, while others can survive in harsh environments for long periods. Many can transform into spores by creating a thick wall that shields them from the majority of the materials used to destroy them. When these bacteria are not in the spore state, they are significantly more vulnerable to these chemicals.
Gram-positive and gram-negative bacteria are two types of bacteria. This feature is due to variations in their cell walls, which impact how they stain when viewed under a microscope. Their reaction to certain chemicals, such as disinfectants, is also influenced by whether they are one or the other.
Bacteria wreak havoc on birds in two main ways:
- Those who assault and damage the cells of the birds, as well as the spaces between them.
- Those who make toxins or poisons that are harmful to birds.
Antibiotics and other medications that are efficient against various germs are available. Quarantine and excellent cleanliness, on the other hand, are vital first lines of defense against these pathogens since they reduce the number of people who are targeted by the medications.
Chlamydia
Chlamydia is a bacterium that is somewhat bigger than viruses. They dwell inside the cells they infect, especially the respiratory system cells. Antibiotics can be used to treat them.
Mycoplasmas
Single-celled organisms that are somewhat bigger than chlamydia. They have a nucleus and a cell wall. Mycoplasmosis, or Chronic Respiratory Illness (CRD) caused by Mycoplasma gallisepticum, is the most well-known disease produced by this bacterium. Antibiotics can help treat diseases caused by Mycoplasma germs. These organisms do not live outside of the host for lengthy periods, thus proper quarantine and hygiene protocols, as well as a sufficient housing de-population period, will ensure effective control.
Fungi
Fungi are creatures that are bigger than bacteria and belong to the plant kingdom. They reproduce by generating spores, which are discharged into the environment. When the circumstances are favorable, the spores begin to proliferate and the cycle begins again.
Birds are harmed by fungi in two ways:
- They enter the body through the respiratory system, where they begin to develop.
- Toxins or poisons are produced, for example, in food. The poison affects the birds when they eat tainted food. Aflatoxin, which is created by some molds or fungi that typically thrive in peanut meal and various litter materials, is an excellent example of this sort of harm. Almost all drugs are resistant to molds or fungus.
Protozoa
Single-celled creatures that are bigger than bacteria are known as protozoa. Protozoa have a complicated reproductive system that permits them to proliferate in large numbers fast in many instances. Coccidiosis in chicken is a nice example of protozoan infections.
Protozoa typically cause tissue destruction in birds. A variety of chemicals have been produced to treat birds afflicted with various protozoans. Others have been created that disrupt the protozoan life cycle and might be used as preventative therapies while the birds gain natural immunity. Coccidiostats are the common name for these anti-infective medications.
Internal parasites
Parasites are parasitic creatures that feed on their hosts.
Internal parasites in chickens are multicellular organisms that reside within the bird and are often found in certain organs.
The majority of internal parasites, especially those prevalent in Australia, can be seen with the naked eye.
While there are a variety of internal parasites seen in chickens, only three are known to be harmful.
These are the following:
- Large roundworms
- Caecal worms
- Tapeworms
External parasites
These parasites are parasites that reside outside of the bird.
Some people devote their whole lives to birds, while others devote only a portion of their lives to birds.
Some irritate the bird, while others are bloodsuckers that, in large enough numbers, can induce anemia.
Some bloodsuckers contain bacteria known as spirochetes, which they inject into the bird during feeding.
Tick fever, for example, is a disease caused by spirochaetes that can kill numerous birds.
Disease prevention
This component of poultry management has to be constantly monitored. In most cases, failing to maintain a high standard will result in an unhealthy flock. The following are the fundamentals of poultry health management:
- Quarantine is the process of isolating the flock from disease-causing germs.
- Hygiene is the eradication of as many dangerous organisms as feasible.
- The implementation of an adequate vaccination program – stimulates the immune system of the birds.
- For illnesses for which there are no vaccinations, the adoption of appropriate preventative drug regimes.
- The implementation of an appropriate monitoring program – to track the presence of disease organisms as well as the success or failure of the hygiene or immunization programs.
Quarantine
The primary requirement is to retain control over disease-causing organisms’ access points. These can enter through a variety of channels:
- Poultry – replenishing a poultry farm by introducing stock as day-old hens is regarded to be the safest approach. Even if they don’t display symptoms, older birds are more likely to be unhealthy or at least carriers of disease.
- Disease-carrying wild birds and other animals are more likely to fly or transfer from one chicken farm to another if the farms are close enough. The simplest approach to avoid this is to maintain a reasonable distance between farms, which should be at least 5 kilometers. The poultry farm should be surrounded by a security fence 2 meters high with a controlled access gate, and all sheds should be secured by protective wire netting from wild birds and other animals.
- Insects and dust blew on the wind from infected to clean farms may convey infectious disease-causing organisms. The simplest approach to avoid this is to maintain a reasonable distance between farms, which should be at least 5 kilometers. The direction of the prevailing wind has an impact on this distance. Insects and dust move farther with the wind than against it, and the existence or absence of obstacles such as hills and thick vegetation collect dust and insects.
- People and cars – the most common visits, including vehicles, are those who have come into touch with other poultry, whether it’s chicken delivery vehicles, feed delivery vehicles, service personnel and their vehicles, or commercial neighbors. Only necessary visitors should be allowed entry, and persons and vehicles should enter through a disinfecting wash facility, with visitors using a shower/change facility. Before entering each shed, disinfectant footbaths and a change of footwear are also suggested. Before entering any poultry house, a shower and change of clothes should be necessary in some cases. The organization of employees on the farm is also crucial. Staff should be confined to a single place if practicable. However, personnel may be required to transfer from one shed to another under certain circumstances. In these situations, the most important criterion is to do so in the safest possible manner. This implies that on the farm, the customary procedure is to advance from the youngest to the oldest flocks, leaving illness flocks, regardless of age, until last.
- No used equipment should be permitted on a poultry farm. Before allowing such entrance or moving equipment from one residence to another, it should be fully cleaned and disinfected.
- Food and water – When an infected bird eats or drinks from a trough, contaminated food or water is left behind. While it is difficult to avoid disease transmission inside a single pen, the choice of feeder and drinker can help to minimize or halt the spread of disease. Open feeders and drinks should never be extended from one pen to another.
- Flies and rats – in addition to the points made regarding distance from other flocks to reduce insect and animal migration from one farm to another, all fly and rodent populations should be managed since they can carry disease-causing organisms and pass them on to the stock.
Hygiene
Microorganisms, especially those that cause illness, are killed by excellent hygiene, and all farms have colonies of microorganisms. As a result, appropriate cleanliness techniques are a crucial aspect of managing poultry health. The phrases quarantine and hygiene are often used interchangeably.
The following are examples of good hygiene practices:
- After each flock has been evacuated, the chicken buildings and equipment are thoroughly cleaned.
- Vehicle disinfection and wash facilities are used.
- The usage of footbaths at each house’s entrance.
- The providing of footwear at each shed’s entrance.
- After washing the shed, use clean litter material instead of reusing litter. Litter should be handled in the chicken house to keep it dry and friable without caking or becoming too damp.
- Taking out all deceased birds daily and properly disposing of them.
- Keeping all residences, adjacent structures, and their surroundings clean and neat.
Disease severity
Disease in poultry may be classified into two categories of severity in terms of flock health management:
- Sub-clinical: an illness with no evident symptoms is referred to as sub-clinical.
The birds do not appear to be unwell, but the infection causes them to develop slower and/or lay fewer eggs. Other species may be predisposed to subsequent invasion by subclinical illness. The only proof that the birds are afflicted is the poorer production efficiency discovered during a performance study. In many situations, this isn’t discovered until after a significant amount of financial harm has been done.
- Clinical disease is one in which the indicators of illness in the birds are more visible. They exhibit the symptoms of the sickness with which they are affected. Clinical illness hurts the flock’s performance, and in many situations, a percentage of the birds die or never return to their prior performance level, leaving the flock unprofitable.
Affected birds, and in many cases recovered birds, are carriers who may be a source of infection for other stock with whom they come into contact, and who may transfer the pathogenic organism directly or indirectly to stock not implicated in this outbreak.
Vaccination
The goal of vaccination is to stimulate the immune system of the bird to develop antibodies that will help it fight illness. While not all illnesses are vaccine-preventable, all possible infectious disease risks should be recognized and a vaccination program devised to assist battle those that are. It may be required to seek veterinary guidance to establish a vaccination schedule that is appropriate for each farm.
The keys to effective vaccination are:
- The potency of the vaccine used and/or its suitability for the disease strain to be controlled.
- The handling and storage procedures for the vaccine during travel and on the farm.
- The use of the recommended application techniques.
- Adherence to the recommended program.
Preventative medication
There are currently no vaccines available to address all disease risks.
To counteract infection by some organisms, it may be required to take a preventative drug.
To identify a suitable preventative medicine program, veterinary consultation may be required.
Monitoring program
The majority of infectious agents are invisible. As a result, having a monitoring program is necessary. This might include:
- The flock is checked daily.
- Autopsies are performed regularly on the farm and in the laboratory.
- Blood is taken for testing at the lab.
- Taking swabs and exposing plates for laboratory analysis.
These strategies can be used to monitor the present illness status, including parasite presence, cleaning success or failure, and vaccination success or failure.