Poultry Red Mite: Welfare Impacts and Control

Key Welfare Considerations

• Dermanyssus gallinae infestations affect an estimated 80% of European laying hen flocks.
• Red mite feed on hen blood at night, returning to structural refuges in the housing during daylight.
• Blood loss from heavy infestations causes anaemia, pale combs, reduced egg production, and weight loss.
• Severe welfare impacts include pruritus, feather pecking, reduced feed intake, and increased mortality.
• Behavioural indicators of red mite infestation include increased restlessness, discomfort behaviour, and poor sleep.
• Haematocrit measurements can quantify the anaemia welfare burden in heavily infested flocks.
• Treatment options include acaricides, heat treatment, silica dusts, and natural predators.
• Fluralaner (Exzolt) systemic treatment has transformed red mite control welfare outcomes in commercial flocks.
• Resistance to pyrethroid acaricides is widespread in D. gallinae populations, limiting treatment options.
• Biosecurity is critical — red mite is introduced via equipment, clothing, and wild bird contact.
• Housing design with smooth surfaces and minimal crevices reduces red mite harbourage welfare risk.
• Regular monitoring using sticky traps and cardboard harbourage traps detects infestations early.
• Natural predators including Hypoaspis miles provide biological control with welfare benefits over chemical approaches.
• Welfare assessments in laying hen flocks should include systematic red mite burden evaluation.
• The economic cost of red mite infestations provides commercial incentive to align with welfare improvements.