Updated November 28th, 2020
A normal chicken’s leg is a thing of wonder: shiny, evenly spaced scales completely cover the leg and top of the foot, giving you the unmistakable reminder that chooks are really little pet dinosaurs.
You know a normal leg when you see one, but it’s harder to notice when it’s not. Scaly leg in chickens often goes unrecognised in flocks until it either gets bad, or you end up at the vet for another reason.
Signs Of Scaly Leg
Scaly leg is caused by a microscopic mite that burrows in the outer layer of the skin. It causes rough, hard whitish crusts and spurs on the feet and legs. Darker areas are the result of the skin cracking and bleeding. The normal shiny scales are typically completely absent.
The Cnemidocoptes mite also affects Budgies, where it causes a crumbly honeycomb appearance to the bill, and canaries, causing long spurs on the legs.
How Chickens Catch Scaly Mite
Most chickens get scaly mite from new introductions to the flock. Therefore you should always check the legs of each new chicken carefully.
However, it’s also possible for wild birds to transmit the mite. This is yet another reason to do everything you can to exclude birds from your chickens’ feeding and roosting areas.
I am personally dubious about stories of the mite coming in on inanimate objects like bedding. My personal view is that cases where the mite suddenly appears in a closed flock are best explained by a subclinical infection of the mite, just like we see with Guinea Pigs.
Treatment Of Scaly Mite
There are many folk remedies you can read online for scaly mite. Most of these rely on the daily application of something that asphyxiates the mites.
I won’t talk about these because I never see them completely eradicate the infestation. Yes, as a vet I’m more likely to see the failures, but I have also never heard of success. The symptoms certainly improve, but there seem to always be a few mites that survive.
Scaly mite is best treated with ivermectin. In Australia this drug is only available in forms for cattle and sheep, and should only be administered by a vet. There are three reasons why:
- The strength of livestock medicines makes overdosage extremely likely
- Ivermectin is a drug with legal restrictions on its sale & storage
- Withholding periods need to be followed closely
The last point is perhaps the biggest disadvantage of using any systemic medications on chickens. Ivermectin is fat-soluble, and will accumulate in egg yolks, which take around 30 days to form. Therefore, to be safe, we routinely double this as the withholding period.
Eggs from chickens treated with ivermectin should not be eaten for two months. Therefore you may want to time the treatment to coincide with a broody period. However, most chickens can’t wait that long.
Treatment Protocol & Success
Ivermectin can be given either orally, on the skin, or as an injection. Personally, I only use it as an injection, and so will you!
Once you see how easy it is to give a chicken an injection, you’ll wonder why you did it any other way. Injections are quick, precise, accurate and effective. With a fine insulin needle, they’re also probably less stressful than other ways to medicate.
I suspect that my bias towards injections is why I have never experienced a treatment failure. A course of ivermectin injections will also treat lice, and worms other than tapeworm.
Every chicken must be treated simultaneously to eradicate the mites. Due to a legal requirement to only treat animals ‘under our care’, you will need to bring in all the chickens for the first visit. Only a single consultation fee is charged if there are no other problems.
We will show you how to give the first dose, and even get you to do one. Then we are happy to supply the following doses to be given at home. However most people prefer us to give each course, and that’s OK too.
Three doses of ivermectin are given at exactly 14 day intervals. The second and third doses are to kill newly hatched mite eggs before they lay eggs of their own.
Lastly, it’s a great idea to do a major spring clean of the coop, run and yard, paying special attention to roosting areas. In theory this isn’t necessary, but you have to do it sometime, so why not now. Muck out the old litter, and scrub or pressure hose roosts, walls and flooring.
Within a few weeks, the crusts and scabs start falling off. After a few months you’ll have those lovely dinosaur legs back again.
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By Andrew Spanner BVSc(Hons) MVetStud, a vet in Adelaide, Australia. These help topics are from a series regularly posted on email and Twitter. Subscribe via email here to never miss a story! The information provided here is not intended to be used as a substitute for going to the vet. If your pet is unwell, please seek veterinary attention.