Category Archives: chicken

Infectious Synovitis

infectious synovitis lesion of the toe join

Infectious Synovitis, also called Mycoplasma Synoviae Infection, MS Infection, Enlarged Hock Disease, Synovitis is an acute to chronic, systemic disease of chickens caused by infection with Mycoplasma synoviae (MS).

It affects the synovial membrane of joints and tendons leaving the chicken unable to walk properly. Chickens with infectious synovitis develop swollen, red, and warm hock joints. They are in so much pain it is difficult for them to walk. The synovial membranes of tendon sheaths become thickened, edematous, with fibrinous exudates accumulating within and around the tendon sheaths.

infectious synovitis of the hock joint


Coccidiosis is one of the most common poultry diseases.


Coccidiosis is caused by protozoan parasites of the genus Eimeria. In poultry, Eimeria affects the intestine making it prone to other diseases (necrotic enteritis) and reducing the ability of this organ to absorb nutrients. 

Between poultry houses, the disease is transmitted by mechanical carriers such as insects and wild birds. In general, good natural immunity is generated after Eimeria infections in poultry and for this reason, coccidiosis is usually a disease that affects young animals. However, the achieved immunity is specific for each of the species of Eimeria and it is not cross-protective between species

The replicative phases of the parasite lead to damage in the intestinal tissues. Individual birds may show no clinical signs or may suffer a mild loss of appetite, weight loss or decreased weight gain, diarrhoea (which can be bloody), dehydration and death. Resistance develops rapidly and infections can be self-limiting, but naïve birds which consume large numbers of oocysts can be severely affected and die. Immunity is strictly species-specific which means that birds exposed to one Eimeria remain susceptible to infection from all other species.


  1. Give the affected chicken Amprolium in drinking water.
  2. Give electrolytes to compensate for the mineral loss due to diarrhoea
  3. Give vitamin E to compensate for the loss due to Amprolium treatment. Otherwise chicks my get crippled due to vitamin E deficiency

Fowl Cholera

Fowl Cholera is a highly contagious disease caused by the bacterium Pasteurella multocida. It affects chickens, turkeys, and water fow.
It infects through mouth and nose and is spread through nasal exudate, faeces, contaminated soil, equipment, and people. The incubation period is usually 5-8 days.

The bacterium is easily destroyed by environmental factors and disinfectants. However, it can stay persist for a long time in the soil.


  • Dejection.
  • Ruffled feathers.
  • Loss of appetite.
  • Diarrhoea.
  • Coughing.
  • Nasal, ocular and oral discharge.
  • Swollen and cyanotic wattles and face.
  • Sudden death.
  • Swollen joints.
  • Lameness.

Post-mortem lesions

  • Sometimes none, or limited to haemorrhages at few sites.
  • Enteritis.
  • Yolk peritonitis.
  • Focal hepatitis.
  • Purulent pneumonia (especially turkeys).
  • Cellulitis of face and wattles.
  • Purulent arthritis.
  • Lungs with a consolidated pink ‘cooked’ appearance in turkeys.


Sulphonamides, tetracyclines, erythromycin, streptomycin, penicillin. The disease often recurs after medication is stopped, necessitating long-term or periodic medication.


Biosecurity, good rodent control, hygiene, bacterins at 8 and 12 weeks, live oral vaccine at 6 weeks.

Capillaria (Capillary or Thread Worms)

There are several species of Capillaria that occur in poultry. Capillaria annulata and Capillaria contorta occur in the crop and esophagus. These may cause thickening and inflammation of the mucosa, and occasionally severe losses are sustained in turkeys and game birds.

In the lower intestinal tract there may be several different species but usually Capillaria obsignata is the most prevalent. The life cycle of this parasite is direct. The adult worms may be embedded in the lining of the intestine. The eggs are laid and passed in the droppings. Following embryonation that takes six to eight days, the eggs are infective to any other poultry that may eat them. The most severe damage occurs within two weeks of infection. The parasites frequently produce severe inflammation and sometimes cause hemorrhage. Erosion of the intestinal lining may be extensive and result in death. These parasites may become a severe problem in deep litter houses. Reduced growth, egg production and fertility may result from heavy infections.

If present in large numbers, these parasites are usually easy to find at necropsy. Eggs may be difficult to find in droppings, due to the small size and time of infection.

Since treatment for capillaria is often lacking, control is best achieved by preventive measures. Some drugs, fed at low levels, may be of value in reducing the level of infection on problem farms. Game birds should be raised on wire to remove the threat of infection. As some species of capillaria have an indirect life cycle, control measures may have to be directed toward the intermediate host. Hygromycin and meldane may be used for control. Additional vitamin A may be of value. Effective treatments that are not approved by the Food and Drug Administration are fenbendazole and leviamisole.

Blackhead disease (histomoniasis)

Blackhead disease (histomoniasis) is an important poultry disease that affects turkeys, chickens, and game birds such as partridges, pheasants, and quail. The disease is caused by the protozoa Histomonas meleagridis, tiny, single-celled organisms that are spread to the bird by the roundworm Heterakis gallinarum.

Lifecycle and Signs of Disease

The lifecycle of the protozoa H. meleagridis is complex:

  • The protozoa multiply in an infected bird’s cecum, a part of its digestive tract;
  • They move to the bird’s intestines where the roundworm H. gallinarum lives;
  • The roundworm eats the protozoa;
  • The roundworm’s eggs become infected with the protozoa;
  • The bird sheds the protozoal-infected roundworm eggs in its droppings.

Healthy birds become infected when they eat food, invertebrates (such as earthworms), or bird droppings that are contaminated with the protozoa. Direct bird-to-bird transmission can also occur within a flock. Because chickens, partridges, and pheasants commonly have the roundworm in their intestines, they often are the source of the protozoal infection for other birds.

Birds with blackhead disease are usually listless and have drooping wings, unkempt feathers, and yellow droppings. Typically, the cecum and liver of an infected bird will become inflamed and develop ulcers. Young birds become sick quickly and usually die within a few days after signs appear. The disease develops more slowly in older birds and they often become emaciated and may eventually die.

Turkeys are highly susceptible to blackhead disease. Once a turkey flock has been infected, 70 to 100% of the birds may die. In one survey, U.S. turkey industry professionals reported at least 50 outbreaks of the disease each year since 2009.1 Blackhead disease is less severe in chickens but can lead to poor health and reduced egg production