Poultry Red Mite Infestation and Flock Welfare

Red mite (Dermanyssus gallinae) is the most economically significant ectoparasite of laying hens, causing anaemia, stress, and reduced welfare in millions of birds across commercial and backyard flocks.

Key Facts

Red mite infestations affect an estimated 80 percent of European laying hen flocks to some degree
Mites feed on blood at night, causing anaemia, weight loss, reduced laying, and increased mortality in heavy infestations
Red mites live in housing structures rather than on birds — they are almost impossible to eliminate entirely from established buildings
Conventional acaricides face growing resistance; spinosad and fluralaner are newer alternatives with better efficacy profiles
Red mites cause behavioural changes including reluctance to enter housing at night, restlessness, and feather pecking
Backyard flock owners frequently underestimate infestation severity because mites are invisible during daylight hours

Welfare Considerations

Heavy red mite infestations cause significant welfare suffering: anaemia from repeated blood loss leading to pallor, weakness, and reduced immune function; chronic stress from nightly feeding that disrupts normal resting behaviour; and feather loss and skin irritation from mite activity. In severe cases, mite-induced anaemia causes death. The psychological welfare of hens in heavily infested houses is significantly compromised — birds that avoid entering housing at night expose themselves to outdoor temperature risk while those that enter face mite attack. Effective integrated mite management — combining monitoring, structural treatment, and licensed acaricide application — is essential for maintaining acceptable flock welfare standards.

What You Can Do

Monitor red mite levels monthly by checking for mites in housing crevices and under perches at night using a torch
Apply licensed acaricide treatments (Exzolt in water or housing treatments) when infestation is detected before it reaches severe levels
Ensure backyard poultry housing is inspected and treated before purchasing new birds to prevent introducing mites to clean housing
Support development and uptake of integrated pest management approaches for red mite that reduce reliance on single acaricide classes