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Depluming Mites

The depluming mite (Knemidocoptes gallinae) is a type of ectoparasite which infects a wide range in bird species, including chickens, ducks, pigeons, turkeys and geese. K. gallinae burrows into the feather shafts and surrounding skin. It causes damage to the skin and feathers. The mites feed on the fluid that oozes out as a result of the burrowing. The constant burrowing causes intense irritation and pain and often results in the bird pulling out their own feathers.

Depluming mites are usually found along the back, neck, head and wings of the bird. These mites require a host to survive and can't survive in the environment. They will spend their entire life on the bird and give birth to live young instead of laying eggs.

The mites are more active during the spring and summer months and reach adulthood in less than 17 days. Chickens can carry low numbers of these mites without showing signs of infection. When a chicken becomes sick and/or unable to preen or dustbathe then the mite population can grow rapidly.

Depluming mites can often be confused with overmating from roosters since they both can result in bare spots of missing feathers along the head, neck and back of the bird.

Clinical Signs

Feather loss along the back and neck

Broken or damaged feathers

Scratching

Restlessness

Molting out of season

Increased preening

Diagnosis

History
Clinical signs
Physical exam

Treatment

Name	Summary
Elector PSP	Sprayed directly on chickens.
Sulfur	Applied as a dust directly on the chickens, added to their dustbathing area or hanging small gauze bags of sulfur dust around the premises.	A Murillo et al., 2016
Fipronil	Sprayed at the base of the neck, tail base, and under each wing and repeat in 30 days	B Speer; Clinical Veterinary Advisor
Pyrethrum	Applied as a powder or a spray directly on the chicken. When treating the bird, apply directly on the chicken's feathers, concentrating on the vent area. Note that it only kills the adult insects, not the larvae and eggs. Therefore, treatment will need to be repeated in 2 weeks.	G Damerow
Permethrin	Applied as a powder (0.24% permethrin) or spray (3 ounces of 10% permethrin is mixed in a 5-gallon bucket of water), directly on the chickens.	G Damerow

Support

Prevention

Provide chickens with a dustbathing area which contains diatomaceous earth.
Proper biosecurity - Keeping wild birds from interacting with your chickens.
Quarantine new flock members.

Scientific References

Martin Ficken, DVM, PhD. Depluming mites in birds Texas A&M Veterinary Medical Diagnostic Laboratory (2020)
Davies, Gaynor. Common ailments of pet hens Veterinary Nursing Journal 31.6 (2016)
Van Velden, Julia. Knemidokoptic mite infections on the Cape Peninsula population of Black Sparrowhawks. Diss. University of Cape Town (2013)
Rajabzadeh, M., S. M. Razavi, and A. R. Homayounimehr. Depluming itch in native fowls in the Iran, a potential risk for commercial chickens. Tropical animal health and production 40.1 (2008)
Titchener, R. N. Inhabitants of avian skin with special reference to ectoparasitic infestations and diseases of poultry skin.. Proceedings of the Royal Society of Edinburgh, Section B: Biological Sciences 79.1-3 (1980)

Risk Factors

Not providing chickens with an area to dustbathe.
High populations of wild birds.
No quarantine procedures when a new bird is introduced in the flock.

Seasonality


Winter	Spring	Summer	Autumn

Etiology

Knemidocoptes gallinae

Also Consider

Lice infestation