**Fowl Mites** is a collective term referring to several species of parasitic mites (class Arachnida) that infest poultry, cage birds, and wild birds. They are severe economic pests in the poultry industry and a common problem for backyard chicken keepers. The two most important species are the **Northern Fowl Mite** (*Ornithonyssus sylviarum*) and the **Red Mite** or **Chicken Mite** (*Dermanyssus gallinae*). These mites suck blood, causing severe irritation, anemia, reduced egg production, and, in heavy infestations, death.
Taxonomy and Classification
Fowl Mites belong to the sub-class Acari. They undergo simple metamorphosis (egg, larva, nymph, adult). A key difference in behavior separates the two main pests:
- **Northern Fowl Mite:** Spends its entire life cycle **on the host bird**.
- **Red Mite (Chicken Mite):** Spends most of its time **off the host**, hiding in cracks and crevices of the coop during the day, and crawling onto the birds at night to feed.
Physical Description
Adult Fowl Mites are minute, typically less than $1$ mm long, barely visible to the naked eye.
- **Northern Fowl Mite:** Usually dark gray or black due to ingested blood. They cluster near the vent and tail of the bird.
- **Red Mite:** Appears gray or white before feeding, but turns bright **red** after taking a blood meal, hence the name. They are visible in large groups in coop crevices during the day.
- **Damage Signs:** Mites are seen crawling on eggs or skin. Heavy infestations cause skin scabbing, feather loss, and a chronic appearance of dirty or matted feathers near the vent.
Distribution and Habitat
Fowl Mites are cosmopolitan pests, found globally wherever poultry or caged birds are kept. The habitat for the Red Mite is the dark, warm crevices of the coop, nesting boxes, and roosts. The habitat for the Northern Fowl Mite is the host bird itself, often clustered in areas difficult for the bird to preen.
Behavior and Damage
Fowl Mites have a rapid life cycle (as fast as 7 days in warm conditions) and reproduce year-round in heated or warm environments. They feed on the host’s blood, causing severe stress and physiological damage:
- **Anemia and Mortality:** Heavy infestations can result in significant blood loss, leading to anemia, weakness, and, particularly in young or stressed birds, death.
- **Production Loss:** Chronic irritation and blood-sucking cause reduced feeding, weight loss, and severe drops in egg production (up to 30%).
- **Coop Infestation (Red Mite):** Red Mites can survive off the host for several weeks, making coop sanitation critical. Infestations are often noticed by people feeling mites crawling on themselves after collecting eggs or handling birds at night.
Management and Prevention
Control requires a dual approach: treating the bird and treating the environment.
- **Environmental Treatment (Red Mite):** Thoroughly clean the coop, removing bedding and debris. Treat all cracks, crevices, and roost areas with approved residual insecticides, silica dust, or diatomaceous earth (DE). The treatment must be repeated several times due to the mite’s rapid life cycle.
- **Host Treatment (Northern Fowl Mite):** Apply approved veterinary acaricides directly to the birds, paying close attention to the vent and tail feathers where mites cluster.
- **Quarantine:** Isolate all new birds before introduction to the flock and carefully check them for mites.
- **Biological Control:** Some beneficial insect species (e.g., predatory mites) can be used, but this is less common than chemical or environmental control.
Conservation and Research
Fowl Mites are managed as high-impact agricultural pests. Research focuses on developing safer, non-chemical acaricides, improving the design of poultry housing to limit mite harborage, and breeding poultry lines that exhibit greater resistance or tolerance to mite infestation.