Scaly leg mites (Knemidocoptes mutans
) are a relatively common ectoparasite (external parasite), which affect backyard and free range poultry flocks worldwide.
These mites invade the scales on the legs and feet (less commonly the neck and comb) of their host, resulting in hyperkeratosis, keratosis, and irritation. The damage caused by the mites predisposes the birds to secondary bacterial infections and deformation and loss of toes which can permanently cripple the bird.
Scaly leg mites burrow into the skin on the birds’ legs and top of their feet, where they will spend their entire life cycle (10-14 days) digging tunnels, eating their skin, laying eggs, and leaving droppings behind. One or more flock members might be infected, since the mites will move from bird to bird.
How do I know if my chickens have scaly leg mites?
Healthy chickens have scales that are smooth and flat. Chickens with scaly leg mites will not have scales which are smooth and flat. They will be crusty, and the scales uneven and raised. The skin will be thickened.
Eventually, the heavy crusting of the scales can start to interfere with joint flexion, resulting in lameness, deformity, and necrosis. In addition, chickens infested with scaly leg mites are at risk of developing secondary bacterial infections and fungal pyoderma.
How do chickens get infected with scaly leg mites?
Scaly leg mites are spread between birds by direct contact with infected flock members. They are initially introduced into the flock through wild birds, rodents, or by already being present within the soil and surrounding environment.
How are scaly leg mites treated?
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.