The Knemidocoptes genus are from the family Epidermoptidae, a group of mites responsible for causing skin, feather and facial lesions on many different species of wild and domestic birds. These types of mites spend all their life stages on their host, and are spread from direct contact between infected and uninfected individuals. They are also extremely tiny mites, and are not visible to the naked eye.
Within the genus Knemidocoptes, there are five species: K. mutans, K. pilae, K. intermedius, K. fossor, and K. jamaicensis. K. mutans and K. intermedius are referred to as the "scaly leg" mites, and invade the scales on the legs and feet of their host, and occasionally the neck and comb. K. mutans most frequently affects poultry, and is found worldwide. K. mutans have a life cycle of 10-14 days.
K. mutans burrow into the epithelium resulting in hyperkeratosis, which is described most often as "crusty-appearance" of the legs and feet. The stratum corneum thickens and honeycombed with mites present within the cavities.