Recognise and Treat Fowl Pox in Chickens

Recognise and prevent fowl pox in chickens 

Although it sounds a bit like chicken pox, fowl pox is not related to the childhood illness.

Fowl pox is a viral infection that is common in chickens. It is not transmissible to humans. Although the severity of infections varies, chickens will recover easily from the milder forms of fowl pox.

How to recognise fowl pox in chickens – signs and symptoms of fowl pox

There are two main forms of fowl pox that occur in chickens. Chickens can have both forms of the disease at once and outbreaks in a flock may not be limited to one form.

Symptoms of both forms of fowl pox include a decrease in egg production, poor growth or weight gain and a loss of appetite. Because fowl pox is often transmitted by mosquitoes, outbreaks are more common in the warmer months but can occur at any time.

The milder form of fowl pox is referred to as the dry form.

  • Dry fowl pox affects featherless areas including the wattles, comb, eyes, face and, sometimes, the feet
  • Symptoms of dry fowl pox in chickens include dry, crusty scabs on featherless areas
  • Scabs usually start out as blisters, before turning yellow and then brown or black
  • Can look like warts or skin growths
  • Lesions can occur on feathered skin, but this is less common
  • It is important not to confuse the dry form of fowl pox with scabs or scars caused by pecking or fighting, with frostbite or with scaly leg mites

The more severe form of fowl pox is known as wet fowl pox.

  • This form of fowl pox affects the mouth and throat, including the windpipe
  • Symptoms of the wet form of fowl pox include lesions in the mouth and throat that look like infected ulcers
  • In severe cases, birds may be unable to eat or drink
  • Obstructions or swelling may interfere with breathing
  • Mortality from this form of fowl pox is high
  • It is important not to confuse wet fowl pox with thrush, which causes white or cream patches in the mouth

Chickens usually recover from fowl pox, and particularly the dry form, within 2-3 weeks. Although most birds seem to develop immunity to the disease after having it, some chickens will have reoccurrences of fowl pox in times of stress. This suggests that even healthy birds without symptoms can potentially carry the disease.

How do chickens get fowl pox?

Fowl pox can be transmitted in two ways: by mosquitoes and by infected chickens.

Fowl pox is most commonly transmitted by mosquitoes. This spreads the disease between chicken coops and properties. A mosquito that has bitten an infected chicken can carry fowl pox in its saliva for 8 weeks.

Fowl pox can also be spread by infected chickens. Chickens with fowl pox shed the disease in their feathers, dander, saliva, blood and scabs. Because dander is almost impossible to avoid, the disease spreads easily between birds. It can also remain in the environment for years. In order to become infected, chickens must inhale or eat infected material, or have it come into contact with a skin wound.

Symptoms of fowl pox usually appear 10 to 14 days after infection. The disease can affect chickens of any age.

How to prevent fowl pox in chickens

Unfortunately, in areas where fowl pox is common it may be difficult to prevent. But there are a few things that you can do to protect your birds:

  • Even healthy chickens can carry fowl pox, so always quarantine new birds. Use a sacrificial bird if possible and ensure your pen is netted to prevent mosquitoes.
  • Vaccinate your chickens if you live in an area where fowl pox is common. Vaccination is usually performed on chicks, although a yearly booster may also be recommended. Consult with your veterinarian.
  • Quarantine sick birds at the start of an outbreak and vaccinate unaffected members of the flock. Also clean and disinfect the coop, and sanitise the drinking water.
  • In warmer areas, screen the coop to prevent mosquitoes and close chickens in early, as mosquitoes are most active at dawn, dusk and in the evening.
  • Prevent mosquitoes from breeding by removing sources of standing water and stocking ponds with native fish that eat mosquito larvae.
  • Iodine in your chickens' drinking water at a rate of 1 teaspoon of 1 % iodine per 4 litres of water can also prevent the spread of the disease when outbreaks are occurring.

How to treat fowl pox in chickens

Unfortunately, there is no treatment for birds infected with fowl pox. However, there are some measures that lessen the severity of the disease and improve recovery. These include:

  • Treating dry form lesions with Vetericyn, iodine or another antiseptic to prevent infection and promote healing
  • Providing antibiotics in the drinking water to prevent secondary infection in sick birds, in particular in birds affected by the wet form of the disease
  • Treating drinking water with iodine at a rate of 1 teaspoon of 1 % iodine solution per 4 litres of drinking water can also promote recovery, in particular from the wet form of the disease

Happy chicken keeping!

Rachael - Dine a Chook Australia