Scaly leg

Scaly leg is a disease of chickens and other birds. It is caused by a parasitic mite, Knemidocoptes mutans. The mite burrows under the scales in the bird's legs, but may also infect other areas, including the comb or wattles. The mite spends its entire lifecycle on the birds and is usually spread by direct contact.

Birds infected with scaly leg have raised or protruding scales, sometimes with a white crusty appearance. Scaly leg is extremely irritating to the infected bird, and in extreme cases can result in lameness.

The disease can be treated by soaking the afflicted bird's legs in soapy water mixed with diluted ammonia, and the encrusted areas scrubbed gently with a soft brush, followed by the application of an insecticide to kill the mites, usually oil based. Petroleum jelly (mixed with sulphur if available), or a commercial chest rub can be used &mdash; the mites are unable to breathe beneath the jelly.

Multiple treatments may be required to completely eliminate the mite, and pen, perches, and nesting areas should be sprayed. Ideally birds should be moved to a new area for at least a month to avoid re-infection from dropped scales that may remain infectious for up to 30 days.