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Four different parasites get called “chicken mites” in everyday conversation, and they behave differently enough that treating the wrong one wastes weeks. Start with the question that actually sorts them: where did you find it?
Which one is it?
| Where you found it | What you see | What it is | The thing that catches people out |
|---|---|---|---|
| Around the vent, on the bird, in daylight | Fast-moving specks on the skin, black grit at feather bases, grey-white eggs | Northern fowl mite — the most common external parasite on poultry | Lives on the bird full time, so daylight inspection finds it. Worse in cool weather. |
| Not on the bird — cracks, perch ends, under brackets | Grey or red specks that scatter under a torch at night; black-and-white deposits in crevices | Red mite / chicken mite (Dermanyssus gallinae) | Feeds at night, hides by day. Survives months off a host, so an empty coop stays infested. |
| Legs and feet | Scales lifted and thickened, crusty white-grey deposits underneath | Scaly-leg mite (Knemidokoptes mutans) | Burrows under the scales. Never pick the crusts off — that is live tissue. |
| Feather bases, especially below the vent | Clusters of white grains cemented to the shaft; straw-coloured insects in the fluff | Lice | They eat skin scale and feather debris, not blood, and they cannot live on humans. |
A fifth, less common: sticktight fleas, which attach in dark clusters to the face and wattles and stay stuck even after they die.
Spotting an infestation early
The signs are the same regardless of species, and they show up before you see the parasite:
- Pale comb and wattles — blood-feeding parasites cause anaemia.
- A drop in laying, and lower feed intake.
- Birds reluctant to go into the coop at night — a strong hint at red mite, because the coop is where they are bitten.
- Restlessness, excessive preening, feather damage around the vent.
Handle the birds weekly, at dusk when they’re calm, and part the feathers around the vent. A flock you never pick up is a flock whose parasites you find late.
Treating it properly
1. Treat every bird, not just the affected ones. Use a product whose label states it is approved for poultry — permethrin-based dusts and sprays are the usual choice — and follow the label, including any egg-withdrawal period.
2. Re-treat every 4 to 7 days, at least three times. This is the step most guides get wrong. No approved treatment kills the eggs, and a northern fowl mite egg reaches egg-laying adulthood in under a week. Re-treating on a 4–7 day cycle catches each hatch before it can breed. Stretch the interval to a fortnight and you are simply farming them.
3. Treat the housing too — essential for red mite. Strip the bedding, scrub, and get an approved product into every crack, perch end and nest-box joint. Red mites live in the structure, not on the birds, and adults can survive around six months without feeding.
4. For scaly-leg mite, suffocate them. Coat the whole lower leg in petroleum jelly, or dip the legs in linseed oil, and repeat weekly for several weeks. It smothers the mites and softens the crusts so the scales can regrow. Mild cases recover fully; severe ones can leave permanently deformed feet, which is why catching it early matters.
What the evidence actually says
Diatomaceous earth: useful as prevention, not as a cure. A peer-reviewed trial in free-range organic layers found DE-dusted hens carried significantly fewer mites than sand-dusted controls, and extension guidance lists food-grade DE in dust baths as a non-toxic option. The same guidance is explicit that it will not eliminate an infestation, because it has no effect on eggs. Provide a permanent dry dust-bathing area and let birds treat themselves; don’t rely on it while a bird is being bled.
Ivermectin: recommended constantly online, not approved for poultry. Extension guidance states this plainly. The practical consequence is the egg-withdrawal problem — no approved use means no established withdrawal period. Leave it to a vet.
Garlic, herbs in the nest boxes, essential-oil sprays: no good evidence that they clear an infestation. Pleasant, harmless, and not a treatment.
Preventing the next one
- Quarantine new birds for 30 days. The most common way parasites arrive.
- Keep a dry dust bath available year-round — dry soil, sand, a little wood ash, optionally food-grade DE.
- Design the coop to be inspectable: smooth removable perches beat fixed rough timber, because red mite hides where you cannot scrub. Our coop plans use perches you can lift out.
- Check monthly in cool weather, when northern fowl mite peaks.
Sources
Identification, life cycles, re-treatment intervals and the ivermectin note: Jacob, J., External Parasites of Poultry, University of Kentucky, published via poultry.extension.org · Mites of Poultry, Merck Veterinary Manual · Diatomaceous earth trial: parasite load, egg production and egg quality in free-range organic laying hens, Poultry Science.
Common questions
- How often should I re-treat for mites?
- Every 4 to 7 days, for at least three rounds. No approved poultry treatment kills parasite eggs, and a northern fowl mite egg can develop into an egg-laying adult in under a week. This is the single most common reason a treatment appears to work and then fails a fortnight later — the interval was too long and the next generation hatched.
- Does diatomaceous earth get rid of chicken mites?
- It helps, but it does not eliminate an infestation. A trial in free-range organic layers found hens dusted with diatomaceous earth carried significantly fewer mites than sand-dusted controls, and university extension guidance lists food-grade DE in dust baths as a non-toxic option — while stating plainly that it will not eliminate mites because it has no effect on eggs. Treat it as ongoing prevention, not as the cure for an active infestation.
- Can I use ivermectin on my chickens?
- Not on your own initiative. University extension guidance states that ivermectin is not approved for use in poultry, which matters practically as well as legally: with no approved use there is no established egg-withdrawal period, so nobody can tell you when the eggs are safe to eat. If ivermectin is genuinely warranted, that is a decision for a vet who can take responsibility for it.
- My birds seem fine in the day but I think something is biting them at night. What is it?
- Almost certainly red mite (Dermanyssus gallinae). Unlike northern fowl mites, red mites do not live on the birds — they hide in cracks in the coop by day and feed at night. Treating only the birds will fail. Inspect perch ends and crevices with a torch after dark, and treat the housing thoroughly.
- How do parasites get into a clean flock?
- Usually on a new bird, and secondly from wild birds and rodents. Quarantine every new bird for 30 days before it joins the flock — it is the cheapest parasite control there is.