Common Diseases Affecting Small Poultry Flocks, Theresia Lavergne, Ph.D., P.A.S., Professor – Poultry LSU AgCenter
The following are some of the diseases that commonly affect small poultry flocks. This is a description of diseases, how they are transmitted, symptoms of the diseases, and treatment of the diseases.
Fowl Pox
Chickens with fowl pox will have scab-like lesions on their combs and wattles (on unfeathered parts of their body). Fowl pox can occur in any age of chickens, and may result in decreased egg production, reduced growth rate, and poor feed conversion.
Fowl pox is caused by a virus. The virus is slow spreading and can take several months to move through a flock. An individual bird will have fowl pox for three to five weeks.
Fowl pox is spread by mosquitoes, by direct bird-to-bird contact, or by bird contact with infected premises or equipment.
There is no treatment for fowl pox.
Fowl pox is prevented by vaccination. The vaccination can be given to birds as young as one day of age.
There is another form of fowl pox that affects the respiratory system of chickens. This fowl pox can be more detrimental and is called “wet” pox.
Infectious Coryza
The signs of infectious coryza are nasal discharge, swollen sinuses, discharge from the eyes, or swelling around the eyes and wattles. When chickens have infectious coryza they may decrease their feed and water consumption, decrease their egg production, and their vision may be affected.
Infectious coryza is caused by bacteria and affects semi-mature and adult birds. Birds will show signs of infectious coryza within three to five days after exposure.
Infecious coryza is transmitted by direct bird-to-bird contact, by inhalation of airborne respiratory droplets, or by contact with contaminated feed and water.
Water soluble antibiotics can be used to help relieve the symptoms of coryza. However, there are no antibiotics labeled for use in egg laying chickens.
Coryza is prevented by good sanitation and management, and by using an “all-in, all-out” system (ie., not mixing new birds with existing birds).
Mycoplasmosis
The signs of mycoplasmosis are respiratory distress, watery eyes, nasal discharge, or swollen sinuses. Reduced egg production, stunted growth, or reduced feed efficiency can occur when chickens have mycoplasmosis.
Mycoplasmosis is caused by the mycoplasma organisms (bacteria).
Mycoplasma is transmitted by direct bird-to-bird contact and by inhalation of airborne respiratory droplets.
Treatment is not always effective and antibiotics have varying success. Mycoplasma is one of the diseases under the National Poultry Improvement Plan. Therefore, if commercial poultry get mycoplasma, treatment is not allowed and the flock is depopulated. Treatment may be allowed in small flocks that are not under the National Poultry Improvement Plan.
Mycoplasma can be prevented by good sanitation and management, and by using an “all-in, all-out” system.
Coccidiosis
Birds with coccidiosis will have bloody droppings, diarrhea, unthriftiness, emaciation, dehydration, and even death. Feed and water consumption will be reduced too.
Coccidiosis is caused by coccidia which is a protozoa. Coccidiosis is found in growing and young adult birds (usually not in birds under 3 weeks of age or mature birds).
Coccidiosis is transmitted by direct or indirect contact with droppings from infected birds.
Treatment is accomplished with an anticoccidial.
Coccidiosis is prevented by the use of a coccidiostat, by good sanitation, or by vaccination.