Red Mites (Dermanyssus gallinae)

by

Red mites, also known as poultry red mites, chicken mites, or blood mites (Dermanyssus gallinae), are small blood-feeding mites that primarily parasitize birds—especially chickens and other poultry. They are a serious problem in both backyard flocks and commercial poultry operations in the United States. Heavy infestations can cause stress, anemia, reduced egg production, and even death in birds.

Although red mites prefer birds, they may occasionally bite humans, causing irritation, especially when infestations are severe.

This article explains how to identify red mites, where and when they occur, and how to prevent and control them effectively under U.S. conditions.

What Do Red Mites Look Like?

Red mites have the following characteristics:

  • Size: About 0.6–1 mm long

  • Shape: Flat, oval body with eight legs (they are arachnids, not insects)

  • Color: Gray or pale when unfed; red to dark brown after feeding on blood

  • Behavior: Very fast-moving and primarily nocturnal

Red mites do not live permanently on chickens. During the day, they hide in cracks and crevices. At night, they emerge to feed on the birds.

Where Do Red Mites Thrive?

Red mites prefer dark, warm, and humid environments, especially where birds roost or nest.

Common locations include:

  • Chicken coops and nesting boxes

  • Cracks and joints in wooden structures

  • Under roosts, perches, and coop flooring

  • Bird nests (domestic and wild birds)

  • Equipment used for egg collection and transport

They spread easily between flocks via:

  • Tools, clothing, and footwear

  • Egg cartons and crates

  • Movement of birds between locations

  • Contact with wild birds

How Are Red Mite Infestations Detected?

Signs of infestation include:

  • Red or dark smears on eggs, nesting material, or coop surfaces

  • Chickens that are restless at night or avoid roosting

  • Decreased egg production and weight loss

  • Pale combs and legs, indicating anemia

  • Weakness or death in young or stressed birds

Nighttime inspection often reveals clusters of red mites on birds and coop surfaces.
A simple test is to wipe roosts or cracks with a white cloth—crushed mites appear as red streaks.

Life Cycle of the Red Mite

Red mites have an extremely rapid life cycle:

  • Development from egg to adult in 7–10 days at 68–77°F (20–25°C)

  • Females can lay up to 300 eggs during their lifetime

  • Eggs are deposited in cracks, crevices, and dark corners

  • Adults can survive up to 8 months without a blood meal

Warm summer temperatures and heated poultry houses allow populations to grow explosively.

How Can Red Mite Infestations Be Prevented?

Prevention should be a routine part of poultry management.

Effective measures include:

  • Regular, thorough cleaning of the coop

  • Sealing cracks and joints where mites hide

  • Frequent replacement and washing of nesting materials

  • Applying diatomaceous earth or silica-based products in cracks and under roosts

  • Using smooth, non-porous materials (plastic or metal) instead of raw wood

  • Quarantining new birds before introducing them to the flock

  • Preventing wild birds from accessing poultry housing

How Are Red Mites Controlled?

Successful control requires treating both the environment and the infestation source.

Mechanical Cleaning

  • Remove birds temporarily if possible

  • Clean out the coop completely

  • Use hot water and high-pressure washing

  • Allow all surfaces to dry thoroughly

Heat Treatment

  • Red mites die at temperatures above 122–140°F (50–60°C)

  • Use heat guns or propane torches carefully on cracks and joints

  • Fire safety precautions are essential

Diatomaceous Earth

  • Finely ground fossil material that dehydrates mites

  • Applied to nesting boxes, cracks, and roost areas

  • Useful for prevention and light infestations

Biological Control

  • Predatory mites (such as Androlaelaps casalis) can reduce populations

  • Most commonly used in large-scale or professional poultry operations

Chemical Control

  • Use only approved poultry-safe products

  • Always follow label instructions carefully

  • Resistance can develop, so chemical treatments should be a last resort

  • Birds should not be treated directly unless advised by a veterinarian

Where Are Red Mites Most Common in the United States?

Red mites are found throughout the U.S. wherever poultry is kept, but infestations are most common:

  • In backyard chicken coops with irregular cleaning

  • In older or poorly ventilated poultry housing

  • During warm summer months

  • In heated coops where mites can reproduce year-round

Red mites are persistent and difficult to eliminate completely. Consistent sanitation, preventive measures, and early intervention are essential. A clean, dry, and well-maintained coop remains the most effective defense against red mite infestations.