DIATOMACEOUS EARTH AND CHICKENS
WARNINGS:
1. Diatomaceous earth is a Class 1 Carcinogen according to the IARC.
2. Always wear eye and respiratory protection when using this product. Inhalation of this product, even the ‘food grade’ version, causes scarring in your respiratory system. You should also wash your clothes and shower immediately after using this product, as it can cause skin abrasions.
3. Diatomaceous earth will drift and can kill bees, pollinators and other beneficial insects. Be extremely aware of this if you choose to use this product. Diatomaceous earth is mainly used as an insecticide and anti-caking agent. Legitimate uses of this product include mixing it into grain as it enters the grain bin to prevent losses due to insects during storage.
4. If you are at all concerned with the environment, you should be aware that diatomaceous earth is strip mined.
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Assumptions of this post:
1.) All ethical poultry keepers have the goal of the happiest, healthiest birds possible. Achieving this goal means using the product(s) that are not only the most effective, but that also work the fastest, and cause the least amount of distress to the bird(s).
2.) That unless your farm is certified organic and you must legally or contractually comply with organic practices to supply your market and therefore earn your livelihood, that you are a logical human being who will use what is best for your birds, provided that it is also safe for your birds (toxicity, withdrawal times, respiratory or other factors) and for the humans who will be both applying any product(s) and consuming any eggs or meat from the birds.
DE and External Parasites
Keeping in mind that the goal for external parasites (mites and lice) should be to have zero external parasites at all times, diatomaceous earth (DE) is not an effective treatment, as it only reduces mite numbers but does not seem to be able to completely eliminate them, which leads to birds being continually reinfested.DE *may* be of some use PREVENTATIVELY for external parasites, assuming your birds are currently mite-free. Mixed into your dust bath at a ratio of 20%, it can help prevent an infestation from taking hold.
HOWEVER, because of the danger to human and poultry respiratory systems, dust baths containing DE must be kept outdoors (unless you have a fancy indoor ventilated area for dust bathing), and since DE works best when it is dry, you need to have a covered dust bath area to really make use of this preventative measure.There is a study that references the ideal ambient humidity for DE. The higher the humidity, the less useful the product is, so if you live in a damp climate, the potential usefulness of DE as a preventative is even further reduced. I didn’t link the study because it’s behind a paywall, but also because it’s just common sense.
This study compared various methods of controlling Northern Fowl Mite. They used a liquid formulation of DE in this study.”Diatomaceous earth (12% by wt, in water) reduced mites significantly only if applied for 2 consecutive weeks, and its effects then lasted <2 wk.”Mullins, B. A., D. Soto, C. D. Martin, B. L. Callaham, and A. C. Gerry. 2012. Northern fowl mite (Ornithonyssus sylviarum) control evaluations using liquid formulations of diatomaceous earth, kaolin, sulfur, azadirachtin, andBeauveria bassiana on caged laying hens. Journal of Applied Poultry Research 21: 111–116. https://www.researchgate.net/publication/261986306_Northern_fowl_mite_Ornithonyssus_sylviarum_control_evaluations_using_liquid_formulations_of_diatomaceous_earth_kaolin_sulfur_azadirachtin_and_Beauveria_bassiana_on_caged_laying_hens
This study, which I also reference below in regards to internal parasites, also looked at external parasites (Northern Fowl Mite). The control group was dusted with sand, while the others were dusted with DE. A more balanced study would have included a group that was dusted with 5% Carbaryl or another commercial formula. “In a subsequent experiment, the effectiveness of DE to treat a Northern fowl mite (Ornithonyssus sylviarum) infestation was tested. Relative to controls, both breeds of hens that were dusted with DE had reduced number of mites.”Since DE was not demonstrated to be able to completely wipe out the mite infestation, we know that this renders it essentially useless for this purpose, since our goal is to have zero external parasites. This study showed that it is no more effective than plain old sand in reducing mite numbers.
Bennett, D. C., A. Yee, Y.-J. Rhee, and K. M. Cheng. 2011. Effect of diatomaceous earth on parasite load, egg production, and egg quality of free-range organic laying hens. Poultry Science 90: 1416–1426.
https://www.sciencedirect.com/science/article/pii/S0032579119420300
DE and Internal Parasites
Some people accept that livestock, including poultry, will always carry some level of internal parasites (worms), and their goal for management is to keep the wormload at a low enough level that it won’t overly negatively impact their animals. This view, used in conjunction with Fecal Egg Counts (FEC) at their Veterinarian’s office, can certainly be successful. Keep that in mind as you read ahead …–This study dealt with internal parasites and DE.”The effectiveness of diatomaceous earth (DE) as a treatment against parasites and to increase feed efficiency and egg production of organically raised free-range layer hens was evaluated in 2 breeds of commercial egg layers [Bovan Brown (BB) and Lowmann Brown (LB)] that differ in their resistance to internal parasitic infections. Half the hens of each breed were fed diets supplemented with DE (2%). Their internal parasite loads were assessed by biweekly fecal egg counts (FEC) and by postmortem examination of the gastrointestinal tract. Supplementing DE in diets of LB hens, the more parasite-resistant breed, did not significantly affect their FEC and adult parasite load.””It did not improve resistance in birds that were genetically more resistant but may help birds that were less resistant to lower their parasite load.”Bennett, D. C., A. Yee, Y.-J. Rhee, and K. M. Cheng. 2011. Effect of diatomaceous earth on parasite load, egg production, and egg quality of free-range organic laying hens. Poultry Science 90: 1416–1426. https://www.sciencedirect.com/science/article/pii/S0032579119420300
In another study on beef cattle, DE had no effect on parasite levels, body weight, average daily gain, dry-matter intake, food conversion or days on food compared with the untreated control steers.
DE and possible other benefits
This same study, referenced twice above already, uses a specific product, Red Lake Earth (RLE). RLE also contains a second ingredient (65% DE, 35% montmorillonite), which the researchers say could be the reason behind any of the benefits shown in the study.”One also must consider that, besides DE, the Red Lake Earth supplement contains 35% montmorillonite. Chemically, montmorillonite is hydrated sodium calcium aluminum magnesium silicate. For internal use, montmorillonite is effective in the treatment of irritable bowel syndrome (Ducrotte et al., 2005) and for the prevention of aflatoxicosis (Phillips et al., 2002). Its copper bearing form has also been shown to improve growth performance in piglets and farm tilapia (Hu et al., 2005; Xia et al., 2005) and effectively remove lead from ingested contaminated feed in pigs (Yu et al., 2006). The combination of DE and montmorillonite may therefore improve the general health of the free-range hens and indirectly boost their resistance to internal parasites.”The study also found that after an initial increased weight gain in the DE group, the control group caught up by 38 weeks of age. The DE group ate more, but did not demonstrate greater feed efficiency. This increased feed intake could be what was responsible for the increased body weight (BW) and egg production – but it is not clear if the DE was responsible.”It is not clear how DE could help hens to maintain their BW and better egg production. Hens fed the DE-supplemented diet consumed more and the increased feed intake could be a significant factor.”After an initial improvement in egg shell quality, by the end of the study, it had decreased well below that of the control group.”However, after 28 wk of age, egg shell quality improved for hens fed the control diet whereas it declined for hens fed DE. By 38 wk of age, egg shell weight and thickness were significantly greater in hens fed the control diet.”Bennett, D. C., A. Yee, Y.-J. Rhee, and K. M. Cheng. 2011. Effect of diatomaceous earth on parasite load, egg production, and egg quality of free-range organic laying hens. Poultry Science 90: 1416–1426. https://pubmed.ncbi.nlm.nih.gov/21673156/
Do keep in mind that the Red Lake Earth brand product has been recalled in the past for containing dangerous levels of dioxins. https://www.inspection.gc.ca/animal-health/livestock-feeds/feed-industry-notices/2017-03-21/eng/1490126867305/1490126868147?fbclid=IwAR08w1m6HKdj4U8nqMMu_J7tAGEzBK-3dCfmvkHCUX6DLiUClnOF8jorO0c
DE and Human Health
This 2019 Healthline article debunks most of the supposed ‘benefits’ of DE and contains links to proper studies for everything. Great read!
CONCLUSIONS:
DE may have some use in a hybrid layer flock that is already healthy as a preventative aid to reducing future infestations of internal and external parasites. However, you need to first ensure your birds and coop are mite-free (via visual check) and worm-free (as confirmed by FEC) for this product to be of any value to you.
For birds who are already somewhat naturally resistant to parasites, DE has minimal value. Also, keep in mind that this product should only be used outdoors in a covered, low-humidity dust bath situation, and that if you are physically dusting birds, you should only be doing it outdoors while wearing a mask and goggles.
You will need to dust your birds frequently if using this product, so be mindful of the animal welfare aspects involved in repeatedly handling and stressing your birds (vs. applying an effective product just once). Be very aware of the product drifting, as it can carry on the breeze for some distance and will kill bees and beneficial insects.
DE may be of use for those who are limited by the constraints of a certified organic status by reducing the number of internal or external parasites. However, be prepared for an ongoing battle when your birds get infested – daily dustings for possibly weeks on end until the mites are gone, and then again daily for weeks 10 days later when the new mites hatch.
You will need to be extremely diligent with your visual checks and FEC to ensure your birds’ parasites are not negatively impacting their health.
Given the cost of ongoing FEC and of DE, this approach may not be financially feasible for anyone not reaping the benefits of increased certified organic product prices. Given the time involved, it may not be physically feasible. Given the level of stress to your birds arising from daily dustings (and breathing the product in daily), it should not be considered ethically feasible for the caring poultry keeper.
As a feed additive, it may be somewhat useful for short-term or early weight gain. However, as it also decreases egg shell quality, it is not something I would personally feed to my birds.
BEST PRACTICES:
External parasites: Those poultry keepers who are not restricted by certified organic status and who are most concerned with the health and well-being of their flock will not find much value in DE when other products will work faster and better on external parasites (Doktor Doom poultry spray, Dusting Powder/Sevin), prevent reinfestation (ivermectin, only on your vet’s advice of course), and are safer for you and your birds’ respiratory systems (ivermectin – be sure to observe the withdrawal time set out by your vet – or Dusting Powder/Sevin applied once and then again in the timeframe set out on the label – wear a mask when applying as well).
Internal parasites:
Have your vet perform a fecal egg count (FEC, sometimes called a float or fecal float) to determine if you need to deworm and what species you need to treat against. Since Piperazine is the only over-the-counter product available that is labelled for poultry, and it only gets round worms, if your birds are infested with another type of worm, you may need to have your veterinarian prescribe another product for you – depending on your provincial/state/national laws, some products can only legally be used off-label or extra-label when they are prescribed. A FEC usually costs $20-30 and may save you time and money because you may not need to deworm at all, or you may need to use a different product than what you have on hand. Be sure to observe the withdrawal time on the label (Piperazine has 0 withdrawal in Canada, but may be labelled differently elsewhere), talk to your vet, and/or check FARAD for the egg withdrawal times.
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