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Scaly Leg Mite Infestation

Other Names: Knemidocoptiasis, Cutaneous Knemidokoptosis

Scaly leg mites (Knemidocoptes mutans) are a relatively common ectoparasite (external parasite), which affect backyard and free range poultry flocks worldwide.

K. mutans burrow into the skin on the chicken's legs and top of their feet. This causes hyperkeratosis, keratosis, and irritation. The damage caused by the mites predisposes chickens to secondary bacterial infections. Left untreated, it can lead to loss of toes and permanent deformation of their feet, crippling the chicken.

Clinical Signs

The scales on the chicken's legs and feet should normally appear smooth and flat. When chickens are infested with K. mutans, their scales are often crusty, uneven and raised. The skin will be thickened.
Signs of scaly leg mites in chickens
Eventually, the heavy crusting of the scales can start to interfere with joint flexion, resulting in lameness, deformity, and necrosis.


K. mutans are spread between chickens by direct contact with infected birds. They are initially introduced into a flock through adding a new chicken who is infected already, or exposure to wild birds or rodents.


In order to initially suffocate the mites and help promote growth of new scales, paraffin oil or petroleum jelly (Vaseline) is applied to the legs and feet of each infected bird. Repeated daily until the old, damaged scales have fallen off, and new healthy scales have grown in. Concurrent treatment with ivermectin is also beneficial.

Clinical Signs

Flaking, crusting, scaling, or roughened skin
Uneven or lifting of scales


  • History
  • Clinical signs
  • Physical exam
  • Skin culture

Reported Cases

  • Case 1: Digit necrosis in a Chickens In a flock of bantam chickens, proliferative skin lesions were observed on the shanks of 6 of 29 birds. Some of the birds also showed digit necrosis. Histologic examination of the necrotic digits revealed Knemidocoptes species in the stratum corneum. No new cases of scaly-leg mite infection occurred in the flock after administration of ivermectin, and treatment halted the progression of the disease process in infected chickens. Ref


Paraffin oil, Coconut oil, Shea butter, or petroleum jelly (Vaseline)Apply over the bird's feet and legs.
IvermectinGiven orally or topically in 3 doses at 0.2 mg/kg of body weight, once every two weeks. Two weeks after the first treatment, the scales should be sloughing off, and by the third treatment, new scales should have grown in.
DO NOTEver cut or pick off scales as this can cause damage to the bird's legs and feet.
MoxidectinPour-on or injectable forms are both effective, and available in 0.5% and 1% preparations.
Dergall (in countries where it's available).



  • Provide flock with a dust bathing area
  • Maintain a clean environment
  • Keep rodents out of coops
  • Prevent contact with wild birds
  • Thoroughly clean and disinfect any tree branches brought in to be used as perches for birds.


Depends on how quick the birds are treated.

Scientific References

Good Overviews


Age Range

More likely to occur in older birds.

Risk Factors

  • Feather-legged chicken breeds are more susceptible.
  • Recent relocation to a new environment.
  • High populations of wild birds

Case Stories