Fowl pox is a very painful condition and one that is hard to get rid of from a holding although the disease itself is not necessarily life threatening. Fowl pox is caused by a pox virus and mostly affects chickens. There is a pigeon pox virus and a turkey pox virus.
There are three possible ways in which the virus can be spread:
- The most common way in which the virus is spread is that it is shed from fowl pox wounds on affected birds and enters its next victim through skin wounds. (Normal healthy skin will act as an effective barrier to fowl pox virus).
- Biting insects can carry the virus from one bird to another.
- Pox viruses that infect mammals can be spread through the air and it is thought that this may be a way for fowl pox to be transmitted.
Photo of Fowl pox on a broiler chicken, courtesy of Paul E. Shkarlat. Aviagen LLC.
Once in the skin the virus reproduces to cause ‘pocks’. These start off as raised areas which then burst releasing a tiny amount of pus to leave scab-like crusted raised areas which are often a brownish colour. These wounds are mostly seen on featherless skin such as the legs, comb, eye lids and wattles. This is called the ‘dry form’ of fowl pox. Signs of the ‘dry form’ are raised crusted areas on the featherless areas of the bird causing some mild irritation. These birds may stop laying and lose weight. In severe cases if the eye lids are affected the birds can find it hard to open their eyes. Birds with the ‘dry form’ rarely die. After about 14 days the pocks heal but can sometimes leave a tiny scar.
Much more rarely the virus can infect the mouth, the oesophagus (food pipe) and the trachea (windpipe) initially to form white lumps in these areas but subsequently these areas join together to create a layer of mucus, pus and dead cells from the mouth lining. This is called the ’wet form’. This mucus/pus/dead cells can obstruct the trachea (windpipe) making it difficult for the birds to breathe (in severe cases choking the bird) and it can be very painful making it hard for the bird to eat. Birds with the ‘wet form’ if severe enough can die.
Once a bird in a flock has been infected the virus will spread very slowly but because of this it may be several weeks before it has infected all the birds.
Treatment of Fowl Pox
There is no specific treatment for pox but it is worth taking them to your vet especially if they have the ‘wet form’ as your vet may prescribe antibiotics to prevent secondary bacteria making the problem worse. If your bird is restless and not eating as much food as normal it is worth giving them Chicken Vet Amino + (which contains amino acids- the building blocks of protein) to compensate for their reduced appetite. Birds may find it very painful to eat but may find it less painful to drink, therefore supplements in their water will be of benefit.
What owners can do is to first of all try to keep the disease out by only buying birds from a reputable source i.e. not local markets. Always check your bird for any wounds or unusual behaviour before you purchase it and take it home. Many conditions such as fowl pox can take a few days/weeks to present themselves following infection so it is recommended to quarantine the birds for three weeks after purchase.
Biting insects can spread fowl pox and as such you should try to keep control of the local insect population. [Red Top Fly Traps are good for this – Ed.]
As with all diseases Improving overall hygiene and keeping the birds as stress free as possible will help. The fowl pox virus is very resistant and can survive in the environment for years. Always ensure that you use a DEFRA approved disinfectant such as Interkokask.
Defra Approved Disinfectants
You can buy Interkokask online here.
To prevent fowl pox there is currently no licensed vaccine in the UK but some vets are using the pigeon pox vaccine. If you have had an outbreak on your holding it is worth asking your vet about the possibility of vaccinating any new additions to your flock.
If you would like more information then please contact Chicken Vet via their website.