Spotted crusty scabs on your hen's comb or wattles this summer? It could be fowl pox, a viral disease that turns up in backyard flocks across Australia every year when the mosquitoes come out. The good news is that most chickens recover, and a little planning goes a long way towards keeping it out of your flock in the first place.
Here's how to recognise fowl pox, what to do if your birds catch it, and how to protect them next season.
What fowl pox is and how it spreads
Fowl pox is caused by a virus that affects chickens and turkeys. It moves slowly through a flock, often taking several weeks to run its course, and it's most common in late spring, summer and autumn.
The main ways it spreads are:
- Mosquitoes and biting insects, which carry the virus from bird to bird and from flock to flock
- Direct contact, especially through pecking wounds and scratches
- Scabs and dust, as the virus survives for a long time in dried scabs shed into the coop
Because mosquitoes do most of the work, a flock can catch fowl pox without ever meeting another chicken. Fowl pox doesn't infect people, cats or dogs.
Dry pox and wet pox: the two forms
There are two forms of fowl pox, and a bird can have one or both at the same time.
Dry (cutaneous) pox
This is the most common and milder form. Small pale bumps appear on the bare skin of the comb, wattles, face, eyelids and sometimes the legs. They grow into raised, wart-like lesions that turn into dark brown or black scabs. In bad cases the lesions merge and swell the eyes shut, which stops the bird finding food and water. Most birds recover within a few weeks.
Wet (diphtheritic) pox
This form is less common but far more serious. Yellowish, cheesy patches develop inside the mouth, throat and airways, making it hard for the bird to eat, drink and breathe. Death rates can approach 50%, particularly in young birds. Any bird with signs of wet pox needs to see a vet.
Symptoms to look out for
| Sign | Dry pox | Wet pox |
|---|---|---|
| Wart-like scabs on comb, wattles and face | Yes | Sometimes |
| Swollen or closed eyes | Sometimes | Sometimes |
| Yellow, cheesy patches in the mouth or throat | No | Yes |
| Difficulty eating or swallowing | If eyes are closed | Yes |
| Laboured or noisy breathing | No | Yes |
| Drop in laying, weight loss | Often | Often |
Scabs from fighting or pecking can look similar, and some respiratory diseases look like wet pox. If you're not sure what you're seeing, an avian vet can confirm it.
What to do if your chickens have fowl pox
There's no medication that cures fowl pox. The virus has to run its course, so the aim is to keep your birds comfortable, eating and free of secondary infections while it does.
- Separate visibly sick birds where practical, so they aren't pecked and can eat without competition
- Keep food and water within easy reach, and offer soft, moist food such as wet mash for birds that are struggling
- Gently clean crusted eyes with saline on a soft cloth so the bird can see to eat
- Leave scabs alone. Picking them off creates open wounds and puts more virus into the environment
- Watch for infection. Weeping, smelly or swollen lesions can mean a bacterial infection on top of the pox, which your vet may need to treat
- Get to a vet quickly if a bird has trouble breathing or swallowing, or stops eating
Birds that recover are generally immune to that strain afterwards. Your vet may also suggest vaccinating unaffected birds during an outbreak to slow its spread.
Preventing fowl pox with vaccination
Vaccination is the most reliable protection. The vaccine is applied with a small two-pronged needle through the thin skin of the wing web, usually when birds are 8 to 12 weeks old, though your vet may advise a different timing.
About a week after vaccination, the site should show a small swelling or scab. This is called a "take" and shows the vaccine has worked. Fowl pox vaccine is sold in large multi-dose packs and is time-sensitive once mixed, so most backyard keepers have it done through a poultry vet or ask a breeder to vaccinate young birds. When buying point-of-lay hens, it's worth asking whether they've been vaccinated against fowl pox.
Reducing mosquito exposure around the coop
Vaccination works best alongside good mosquito control, especially through the warm, wet months:
- Tip out standing water in buckets, pot plant saucers and old tyres every few days
- Change waterers daily and keep them clean
- Fit fine mesh over coop ventilation where mosquitoes are a problem
- Lock birds in at dusk, when mosquitoes are most active
- Check new birds carefully and keep them apart from your flock for a few weeks before introducing them
- Clean out the coop regularly, as dried scabs can carry the virus for a long time
Keeping your flock pox-free
Fowl pox is unpleasant, but it's very manageable. Vaccinate young birds, keep mosquitoes down through summer, and check your flock's combs, faces and mouths regularly so you catch problems early. If you spot anything unusual or have questions about keeping your chickens healthy, pop into the store and chat to our bird team.
