A disease (illness) in poultry is a disruption of the body's normal functions, and the degree of this disruption determines the severity of the disease. Depending on the cause of the disease, chickens are divided into:

 

• viral (caused by viruses);

• bacterial (bacteria);

• protozoa (protozoa such as coccidia);

• fungal (fungi such as aspergillosis);

• metabolic or nutritional diseases (lack of nutrients, poisoning);

• surgical (various injuries and wounds).

The consequences caused by the occurrence of the disease can threaten with large economic losses.

 

• Mortality - with some chicken diseases, it can reach up to 100% of the population.

• Decreased productivity - growth can decrease by up to 50% of the norm, accordingly increasing feed consumption.

• Reduction in slaughter yield - the amount of poultry culling can increase up to 25% directly at the slaughterhouse due to non-compliance with standards.

• Treatment costs.

• Costs for disposal of fallen poultry.

• Loss of product attractiveness.

 

To prevent such consequences, work is being done to prevent diseases. Disease prevention is based on the following factors.

 

• Increasing the body's resistance (resistance to the penetration and development of pathogens) - by using the body's internal defenses, such as vaccination and appropriate feeding and housing conditions. Lack of nutrients or an increased content of harmful gases in the poultry house can be a factor that predisposes to the occurrence of infectious diseases in poultry due to a decrease in the body's resistance level.

• The number of pathogens entering the body can be minimized by using a biosecurity system (external protection of the body). Coccidiosis is a good example of the interaction between the number of parasites and the severity of the infection, since the morbidity and mortality of birds directly depend on the number of oocysts consumed. Environmental conditions also strongly influence the disease process, since the condition of the litter affects the sporulation of oocysts and their preservation. A similar situation is characteristic of many infectious diseases.

• The ability of an infection to cause disease. This parameter depends very little on us and therefore must be constantly monitored to ensure the adequate functioning of the above-mentioned defense systems.

Treatment of a bird should begin first of all with the correct diagnosis (establishing the cause of the disease by its consequences - signs), since the method and treatment regimen for different causes of the disease are completely different. Diagnosis depends on three important factors:

 

• Knowledge of the normal appearance and structure of poultry organs (anatomical and physiological features), normative indicators of laboratory tests (virology, bacteriology, chemical analysis), etc.

• Knowledge of the symptoms of diseases and the most characteristic damage to the body during illness.

• Sufficient volume of examinations or autopsies (do not make a diagnosis based on only 1 head) and laboratory tests for differential diagnosis (since many signs are common to a number of diseases).

 

This section describes the main diseases of farm poultry found in Ukraine, their symptoms and methods of prevention.

The article was prepared based on the materials of the book "Diseases of Broilers. Practical Guide to Prevention and Treatment.", Skyba B.S., Grechikhin S.N.