Fowl Pox is a very painful slow-developing viral infection affecting both chickens and turkeys. It is quite common throughout Australia, especially in summer, when flies and mosquitoes are everywhere.
There are two types of fowl pox: wet and dry. A chicken can be infected with one type or the other, or even sometimes both at the same time.
Typical symptoms of either type of fowl pox include:
- lack or loss of appetite
- weight loss
- some lethargy
- a reduction in egg laying
- lesions that look like black pinhead scabs following after white pustules or sores on un-feathered areas.
- respiratory symptoms like difficulty breathing.
- red and inflamed mucous membranes and/or eyes.
- round black ashy scabs on the comb that seem to remain forever.
- flat yellow lesions in the mouth
Some cases of both types of fowl pox will also result in red, irritated, weepy eyes that eventually crust over and puffy eyelids that eventually close, causing a temporary loss of vision.
Mortality is usually low in affected flocks. Reduced egg production and poor weight gains are the greatest impacts. Expect losses to be between 1% and 10% of the flock. Young, old, or already sick birds or those with parasites will likely succumb.
Dry Fowl Pox
Chickens affected with the dry form of Fowl Pox will develop small bumps or raised areas that eventually pop open and secrete pus. These lesions occur on any non-feathered areas such as combs, wattles, beaks, eyes, earlobes, and legs.
These bumps grow in size and darken from yellow to brown to black as rough scabs form.
The scabs will then dry up and fall off on their own, usually after two or three weeks, leaving behind smooth pink scar tissue.
Those fallen scabs contain the pox virus which can then infect other flock members.
The impact of this virus may cause secondary side effects of weight loss and a decrease in egg-laying. Lesions occurring on a chicken’s eyelid may cause such discomfort that a bird may find it difficult to open its eyes. Your infected chooks will feel pain and irritation.
The dry form is the milder form of the two and usually does not end in death.
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.
Wet Fowl Pox
Wet Fowl Pox starts off as whitish, cheesy patches in the throat and mouth that spread and grow into bumps. A chicken’s trachea may appear reddened and inflamed.
The wet form is the more serious form of the two due to the fact that as the lesions grow and develop they may block air coming into the trachea causing suffocation. Also, birds may not be able to eat or drink causing eventual death.
Fowl Pox can often begin as the wet form and spread as the dry form and vice versa. Also, this virus can appear in both forms simultaneously.
How is Fowl Pox Spread to Backyard Chickens?
Fowl pox is initially spread to chickens by mosquitoes biting them and is more prevalent in the early spring, although can be a problem during the winter when chickens tend to be closed up more in their coops or houses.
Fowl Pox can also be introduced to a backyard flock through an infected chicken being added to the flock.
It is then spread throughout the flock through direct contact from other chickens pecking at the scabs on an infected chicken’s face or comb. It can also be spread by chickens scratching on the ground where the scabs have fallen off.
Diagnosing Fowl Pox
This is a very slow-spreading virus and you do have time to isolate the infected birds and tend to them without them wreaking germ havoc throughout your entire flock.
The dry form of Fowl Pox can be diagnosed easily enough due to the highly recognizable crusty scabs; however, the wet form of this disease can pose difficulty as the symptoms mimic those of other respiratory illnesses.
Microscopic analysis of your chook’s skin cells is needed to ascertain a definite diagnosis of the wet form.
If unsure, definitely visit a vet.
There is no known treatment or cure for the fowl pox virus. There are several things you can do to ease your flock’s discomfort during an outbreak- keep birds comfortable, limit stress, and apply antiseptic to scabs
If you find you have an outbreak:
- Thoroughly clean and disinfect the coop and run area.
- Move them if you can.
- Empty the dust baths and refill with fresh sand and diatomatous earth or wood ashes.
- Make sure the surfaces are properly cleaned and if necessary rub them down with sandpaper and retreat the wood.
- Give supporting treatments to make the chickens more comfortable.
- Quarantine sick birds well away from healthy ones.
The biggest concern when Pox infects the flock is to keep immune systems running at their best. Depending on the size of the flock, birds can and should be given vitamins that strengthen the defenses of the skin and mucous membranes, boost respiratory and ocular health, and promote rapid healing.
More serious sores run the risk of getting infected, so try and prevent infection and encourage healing. Applying a first aid salve such as manuka honey or cetrigen to the scabs can help. Or you can apply some iodine to the scabs. The scabs should not be removed.
The duration of the Fowl Pox virus is approximately 10 – 14 days; however, if an entire backyard flock is infected, the duration can extend for several more weeks. Most chickens will be immune following the recovery period. A small percentage though will remain carriers and succumb to the virus when feeling stressed.
Chickens usually recover from Fowl Pox, particularly the dry form, within two-three 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.
Remove standing water that might harbour mosquitoes and plant aromatic herbs around the coop to repel mosquitoes.
Some good choices for herbs that repel mosquitoes are:
- bee balm
- cat mint
- citronella (lemon grass)
Other things that can be done to try to prevent fowl pox include:
- practicing good biosecurity
- quarantining new flock members
- keeping a closed flock
- cleaning the chicken coop and run regularly to remove infected scabs and debris
Once your flock has fully recuperated, be vigilant about regular flock check-ups. Be on the lookout for any small scratches that could become a breeding ground for the Fowl Pox virus.