Scaly leg mites in chickens

Last updated: October 2026

Scaly leg mites (Knemidokoptes mutans) are tiny burrowing mites that live under the scales of a chicken's legs and feet, making the legs thick, crusty and raised^1,2. They spread by direct contact and complete their whole life cycle on the bird². Treatment softens and removes the crusts with an oil such as petroleum jelly, repeated for at least two weeks, plus treatment of the coop^1,2.

What are scaly leg mites?

The scaly leg mite (Knemidokoptes mutans) is smaller than the northern fowl mite, about 1/100 inch, pale gray, with a flat, circular body¹. It lives under the scales of the legs and feet and tunnels into the upper layers of the skin, where it lays its eggs³. The mite infects both wild birds and domestic poultry and lives on areas of unfeathered skin².

Knemidokoptes mutans is a burrowing mite that completes its entire life cycle on the host⁶. It burrows into the deeper layers of the skin of the unfeathered legs, feeds on fluids that ooze from the area, and adult females lay eggs in the tunnel, where the young pass through larval and two nymphal stages before becoming adults⁶. Under the microscope the mite is round, 0.2 to 0.4 mm across, with four pairs of short, stumpy legs⁶.

Its close relative, the depluming mite (Knemidokoptes gallinae), also burrows under the skin and lays its eggs there, but it targets the skin at the base of the feathers, mostly on the wings and abdomen, rather than the legs^4,7. Birds infested with depluming mites pull out their own feathers⁴.

What are the signs of scaly leg mites?

The mites burrow into the skin of the shanks and feet, causing irritation, swelling, enlarged scales and a thickening of the outer skin, so the lesions carry white, powdery, flaking crusts². The skin of the shanks looks thickened and the scales visibly protrude². The normal shiny, smooth shank turns ash-colored or dark with a heavily scaled look, and the intense itching leads birds to peck at their own legs⁶.

Scaly leg mites are diagnosed from the signs plus a skin scraping in which the small round mites are found under a microscope^5,6. A veterinarian or diagnostic laboratory can confirm the mite if the crusts look unusual.

How do chickens get scaly leg mites?

Transmission is by direct contact, and all life stages occur on the bird². Spread through a flock is slow², and for Knemidokoptes mites in general, prolonged contact appears necessary for transmission⁵. Although scaly leg mites prefer to live on birds, they can also survive in the poultry house¹.

Scaly leg mites are occasionally found on poultry in Mississippi, particularly in private farm flocks⁴. They are reported to be highly prevalent in adult poultry and frequently seen in free-range and backyard systems⁶. They thrive on wet ground, attaching first to the toes and gradually moving up to cover the leg⁶.

How do you treat scaly leg mites on chickens?

Each affected bird needs treatment². Daily application of an oil-based product such as petroleum jelly, paraffin or mineral oil softens the crusts, and the legs can then be washed with mild soap to loosen and remove them; continue for at least 2 weeks or until the legs look normal². Coating the entire leg with petroleum jelly or dipping the legs in linseed oil suffocates the mites and moisturizes the scales at the same time¹.

Insecticide treatment is an option, but it must be given on the advice of a veterinarian². Ivermectin is not approved for use in poultry¹. It is against the law to use pest control products off-label in food animals without a veterinarian's supervision, so any product used must be labeled for poultry⁸. Follow the product label, including withdrawal times for eggs and meat⁸.

In long-standing cases, response to treatment may be slow or incomplete because the legs have already changed in ways that are close to permanent⁵.

• Soften: work petroleum jelly, paraffin or mineral oil into the scales daily².
• Lift: wash the legs with mild soap to loosen and remove softened crusts².
• Smother: keep the whole leg coated with petroleum jelly, or dip it in linseed oil¹.
• Persist: keep going for at least 2 weeks, or until the legs return to normal².

Do you need to treat the coop for scaly leg mites?

Yes. Because scaly leg mites can survive off the bird, the entire poultry house must be treated to clear an infestation³. Treat the inside of the house, making sure the nesting area, roosts and any cracks and crevices are covered¹.

Use only a product whose label lists poultry and the pest, and read the label before you buy; the label is the law⁸. For the wider coop cleaning sequence used against all poultry mites, see the coop cleaning guide linked below.

How do you prevent scaly leg mites in a flock?

Inspect the flock regularly, monthly or every two months, for mites and lice⁸, and include the legs and toes of each bird in the check⁶. Because the mite passes by direct contact², check the legs of any new or returning bird before it joins the flock, and treat it first if the scales look raised or crusty.

Treat the house along with the birds, since the mites survive in the poultry house¹. Raised, crusty scales on one bird are a reason to examine every bird, because the mite spreads slowly through a flock by direct contact².