By: Gregory S. Archer
Northern fowl mites
The Northern fowl mite (Ornithonyssus sylviarum) is the most common external parasite found on poultry. It feeds on blood and can cause anemia if the poultry is heavily infested. The mite’s development from egg to egg-laying adult takes about one week under optimum conditions—cool months are more favorable than warm ones. Though adult mites do not lay eggs in large numbers, mite populations on a susceptible bird can exceed 20,000 in only a few weeks. Clinical signs of infestation include decreased egg production, growth rate, and feed consumption. Northern fowl mites also can bite humans causing itching and skin irritation. Northern fowl mites appear as tiny specks moving on the skin—they are found most commonly on the vent area of poultry.
Treatment: Insecticides that effectively control Northern fowl mites include Prozap Insectrin Dust, PoultryGuard, and Ivermectin. Organic insecticides derived from chrysantheniums will also control Northern fowl mites. Food-grade diatomaceous earth (DE) in dust baths may also be used as a control method. DE is an abrasive and will kill the mite by removing its oily or waxy outer cuticle layer.
Scaly leg mites
The Scaly-leg mite (Knemidokoptes mutans) is smaller than the northern fowl mite and lives under the scales on bird’s legs and feet. They tunnel into the upper layers of skin where they lay their eggs. Signs of infestation include the bird’s legs becoming thick and crusty. Severe cases may cut off the blood supply to the toes, and the bird may lose toes.
Treatment: Ivermectin is an effective insecticide for this mite. Non-insecticidal treatment methods include coating the entire leg with petroleum jelly or dipping the legs in linseed oil. This will suffocate the mites and moisturize the scales at the same time. Although scaly-leg mites prefer to live on birds, they can survive off the bird as well. To eliminate an infestation you must also treat the entire poultry house.
The Chicken mite (Dermanyssus gallinae), also known as roost mites or red mites, commonly infest poultry and humans around the world. Unlike the northern fowl mite, it does not live on the bird and can be easily controlled by using an appropriate insecticide. The chicken mite is probably a greater problem in floor nests and on floor-housed birds. During the day, the chicken mite lives in secluded areas around poultry house or coop. At night, the mite crawls onto the bird and feeds on its blood. Infestations may go unnoticed unless birds are examined at night. The life cycle of the chicken mite is 7 to 14 days so, as with the northern fowl mite, heavy infestations can build up quickly if not controlled.
Treatment: To effectively eliminate an infestation, you must treat all the birds and the poultry house. Insecticides such as those mentioned above are all effective. Given the short life cycle of this parasite, birds and houses must be re-treated every 4 to 7 days. Re-treating is also needed more often because the adult mites can survive for up to six months without feeding.
The Sticktight flea (Echidnophaga gallinacea) can usually be found on the skin and wattles of infested birds. Unlike many chicken-infesting mites, these fleas can survive and live on other animals, including dogs, cats, horses, and humans. Sticktight flea mating usually occurs on the bird. Female fleas lay eggs, which then drop to the floor or into the litter. The flea eggs hatch in a few days, and slender white larvae feed on debris in cracks and litter on the floor.
The larvae spin cocoons and pupate. Adult fleas then emerge from the pupal cases. The Sticktight flea’s life cycle completes in one to two months.
Treatment: Exposed fleas and litter are commonly treated with Sevin dust. An alternative to Sevin dust is to coat adult fleas with petroleum jelly, which will suffocate them. Since treatment kills only the adult females, it is necessary to repeat the treatment weekly to catch newly hatched fleas.
The chicken body louse (Menacanthus stramineus) and the shaft louse (Menopon gallinae) are the species of lice most commonly found on poultry. Lice lay their eggs on the birds’ feathers, typically near the base of the shaft. Infested birds may appear agitated because these lice irritate their skin. These birds will have damaged feathers and generally appear to be in poor health. These lice irritate birds by chewing the skin around the base of their feathers, but they do not suck blood as do mites. The constant irritation these lice cause often leads to stressed birds. Poultry lice only leave an infested bird when moving to another bird. A female louse can lay as many as 60 eggs and the typical egg to adult cycle requires about 30 days. Clinical signs may also include reduced feed intake, slowed growth, and declining egg production.
Treatment: The insecticides that are effective on northern fowl mites can also be used to control lice.
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