Is diatomaceous earth safe for chickens?

Last updated: October 2026

Eaten, diatomaceous earth passes through the body largely unabsorbed, and FDA rules allow it in animal feed at up to 2% of the ration as an anticaking agent^1,2. The real risk is the dust: it irritates the eyes and airways of birds and keepers, and any crystalline silica it contains can scar lungs over years of exposure^1,7,8.

What is diatomaceous earth, and how does it act on mites?

Diatomaceous earth (DE) is made from the fossilized skeletons of diatoms, tiny aquatic organisms whose shells are silica (silicon dioxide)¹. Most DE is amorphous silicon dioxide, but it can contain very low levels of crystalline silicon dioxide¹. The first pesticide products containing DE were registered in 1960 to kill insects and mites¹.

DE works physically rather than as a poison: it does not have to be eaten, and it kills insects and mites by absorbing the oils and fats from the outer cuticle so they dry out, while its sharp edges speed the process¹. On a mite such as the northern fowl mite (Ornithonyssus sylviarum), the dust strips the thin waterproof wax layer, so the mite loses water and dies⁶. It stays effective only while it is kept dry and undisturbed¹.

What are the risks of diatomaceous earth for chickens and keepers?

Breathing the dust is the main concern. Inhaled DE can irritate the nose and nasal passages, and a very large amount can cause coughing and shortness of breath; it can also irritate the eyes and dry the skin¹. A review of physical mite controls notes that DE dusts carry inhalation risks and that fine dusts can affect the human respiratory tract, which is one reason liquid silica formulations were developed⁸.

The form of silica matters. Inhaled amorphous DE is rapidly cleared from lung tissue, while crystalline particles are smaller and may accumulate in the lungs and lymph nodes¹. The amorphous form is associated only with mild, reversible lung inflammation, whereas long-term inhalation of crystalline silica is associated with silicosis and chronic bronchitis¹. Respirable crystalline silica causes silicosis, an incurable lung disease, as well as lung cancer, chronic obstructive pulmonary disease and kidney disease, typically after years of occupational exposure⁷. Amorphous silica is regarded as far less hazardous to animals and people than the crystalline form⁸.

For birds, the evidence on swallowed DE is reassuring: when DE is eaten, very little is absorbed and the rest is rapidly excreted¹. DE is commonly encountered by birds and wildlife and is not known to cause them problems, although no formal wildlife toxicity evaluations were found¹.

Does diatomaceous earth control chicken mites and lice?

It helps, but it does not clear an infestation on its own. Food-grade DE in dust baths may help control mites but will not eliminate them, because it has no effect on mite eggs⁶. In a study of free-range organic layers, hens dusted with DE carried fewer northern fowl mites than undusted hens³.

Against the poultry red mite (Dermanyssus gallinae), which hides in coop cracks, results depend on coverage and humidity. In laboratory tests every inert dust killed red mites, but efficacy was significantly lower at 85% relative humidity than at 75%⁴. Brief contact with lightly treated surfaces killed mites as fast as heavy dusting, so the authors stressed thorough treatment of all surfaces in the house⁴. DE suppresses red mites when it is applied thoroughly to their hiding places in cracks and crevices⁸.

Field results are more modest than laboratory ones. Two DE-based products killed all adult red mites within 48 hours in the laboratory, more slowly than synthetic amorphous silica products⁵. In commercial layer houses treated with DE, the first mite colonies reappeared 12 weeks after stocking and kept growing, and follow-up spot treatments slowed but did not reverse the build-up⁵.

Can chickens eat diatomaceous earth in their feed?

Yes, within a set limit. Federal feed rules allow DE as an inert carrier or anticaking agent in animal feeds at no more than 2% by weight of the total ration, with limits on lead, arsenic and fluorine². Food-grade DE products are purified and may be used as anticaking materials in feed¹.

Claims that feed-grade DE works as a dewormer rest on limited evidence. In one study of organic free-range layers fed a 2% DE diet, one breed had significantly lower Capillaria egg counts and Heterakis worm burdens, while the more parasite-resistant breed showed no significant change³. Hens of both breeds on the DE diet were heavier, laid more eggs and ate more feed, with no difference in feed efficiency³.

How do you use diatomaceous earth around a flock with the least risk?

Choose a product made and labeled for the use you intend, and follow the product label, including any first aid directions¹. Exposure happens when people breathe the dust, swallow it or get it on skin or in eyes, for example while applying it or entering a treated area before the dust has settled, so reading and following the label limits it¹.

Keep the dust where it does its job and out of the air. Mites are killed by contact with treated surfaces, so a thorough, even treatment of cracks, roosts and nest areas does more than heavy dusting^4,8. Because DE only works while dry, it suits dry housing better than damp litter or humid coops^1,4. Where respiratory exposure is a concern, liquid silica formulations reduce airborne dust⁸.

Treat DE as one tool. Mite eggs survive it, so mite programs still rely on repeated, labeled treatment of birds and coop on a schedule that catches newly hatched mites⁶.

• Apply when dust can settle before birds and people return¹.
• Work it into cracks and crevices rather than broadcasting clouds of powder⁸.
• Keep treated areas dry, since moisture stops DE from working¹.
• Store products where children and pets cannot reach them¹.