May 18, 2012

Diatomaceous Earth, DE. The Benefit/Risk Analysis from Two Experts

DE, Diatomaceous earth- the risks as discussed by two experts
Whether or not to use food grade diatomaceous earth (DE) in one's flock is a decision each chicken-keeper must make for themselves. As a new chicken-keeper, I read quite a lot about DE before purchasing a ten pound bag, thinking that the claimed benefits sounded tremendous, but I wondered whether it was possible for a product that claimed to fix so many problems in humans and animals could be the real deal. I had also read reports of the carcinogenic effects on humans breathing DE  and the package warnings to wear a respirator when using it, both of which scared the daylights out of me.

Chickens maintain their feathers and skin and control parasites by dust bathing, which is no more than a dry dirt bath. Some claim that adding DE  to the dust bathing area combats external parasites (mites, lice, fleas) and that adding it to their feed controls internal parasites (worms).
Chickens in dust bath area consisting only of sand
Members of my flock, enjoying a nice, communal dust bath.

As a lawyer, when reading about the benefits of any product, a red flag always goes up in my mind when I read product label claims prefaced by "may, might or could,"  particularly when written by a company selling the product. For example: "...the addition of (DE) to chicken feed MAY also provide additional benefits including increased body weight, egg production and egg quality as well as decreased internal parasites (in poultry with a lower natural resistance)." Okay, it may. But it may not. Who knows? Not I.
Food grade Diatomaceous earth
Whenever I have technical or scientific questions, I defer to known, respected, qualifed experts for guidance.  In deciding whether to use DE in/around/with/on/near my backyard chickens, I looked to two highly qualified, experienced and educated professionals in the chicken-keeping world for their opinions about the claimed benefits and any dangers of food grade diatomaceous earth: Gail Damerow and Dr. Mike Petrik, DVM, MSc, a practicing chicken veterinarian.

According to Gail Damerow in The Chicken Encyclopedia, adding diatomaceous earth, wood ashes or lime-and-sulfur garden powder to their dust bath is hazardous to their respiratory health and should be avoided unless they are "seriously infested" with parasites. Even in that case, she writes, "the benefit may outweigh the danger of TEMPORARILY adding such materials." (p. 93 emphasis added)

Damerow also states: "Diatomaceous earth is also sometimes fed to chickens as a dewormer, which supposedly causes dehydration and death to internal parasites. But when combined with a chicken's saliva, diatomaceous earth softens and loses its cutting edge. The only way it could dehydrate internal parasites would be if it contained a hydrophilic substance that draws moisture from a parasite's body, and such a substance would equally affect the chicken's innards. On the other hand, diatomaceous earth contains a lot of trace minerals that are beneficial to chickens, even if it does not act as a dewormer." (p. 84)
I also asked Dr. Mike Petrik, DVM, MSc, aka: The Chicken Vet, for his thoughts on the subject. He is a practicing veterinarian who works with professional farmers and has overseen the care of millions of laying hens in his decade+ of practice. What follows is his written response.
Answers from The Chicken Vet, Dr. Mike Petrik, DVM, MSc on food grade diatomaceous earth, DE
"The question regarding diatomaceous earth is almost a question of philosophy. Many people are of the mindset that "natural" is better, and that there is an automatic benefit to anything that is found in the dirt, plants or animals around us. I (being trained in a western medical-type program) don't believe this to be the truth. Diatomaceous earth (DE) is a great example of this. DE is fossilized algae. Translated, it is ~90% silica (sand), 2-4% alumina (a component of aluminum), and 0.5-2% iron oxide (rust). I can find the same stuff on the floor of any autobody repair the result of sandblasting old cars. 

The theory is that DE is dehydrating because of the sand content, and because the algae are microscopically jagged, they scratch the waxy coating on parasites, allowing them to be killed by dehydrating the worm, tick, cocci or flea. It is touted as a "natural" worming medication and external parasite medication. What you need to realize is that the gut is full of water (making it very hard to dehydrate anything), and that it takes a long exposure time to kill multicellular (ie ticks and mites) parasites. 

I'm also a little leery of any product that claims to do everything....diatomaceous earth claims to be useful in animals, on animals, in the walls of barns, coops and houses, as a pasture treatment, in the yard and garden, and as a treatment for granaries. DE kills bacteria, viruses, absorbs and neutralizes mercury, eliminates drug residues, absorbs organophosphate pesticides, etc, etc. Really? To be honest, all the scientific literature is very equivocal on the usefulness. Some studies find "trends", but very little statistical significance, some studies say that DE is poorly effective at a relative humidity above 85%. One study showed more parasites in one breed of hen fed DE, and less parasites in another breed of hen fed DE.

At the end of the day, my feeling is that, if you want to treat the parasites in your flock, use a treatment that works....has been designed to work, and has been proven to work. A well-conceived parasite program that uses different classes of drugs, observes withdrawal times, and will effectively control parasites as well as resistance.

I don't believe that there is much risk in using DE in your hens, but I am afraid that you may believe that you are controlling parasites when, in fact, you are mostly feeding sand. I apologize to any "anti-drug" advocates that may be offended by my stance in this regard, but I have seen too many instances of treatments that served only to allow animals to suffer infections until regular treatments are finally commenced."

Dr. Mike Petrik, DVM, MSc,
The Chicken Vet
Dr. Mike Petrik, DVM, MSc on the subject of food grade diatomaceous earth

Kathy Shea Mormino, The Chicken Chick®


  1. Excellent information! I have used this substance for one season in my garden and on my birds and I found that ,in reality,it does little but cost money. No effect on garden bugs and the chickens mites were better controlled by a poultry safe dust I found much cheaper in Tractor Supply!! I would love to think of myself as a natural poultry keeper, but the birds' health is way more important to me!!

  2. Great information! I am new to having chickens and I have heard conflicting views on the use of DE (almost bought some the other day, but wanted to do a bit more baby chicks are little so I had some time before they have to go out to a coop). I am so happy you posted this when you did! Thanks so much!
    ~Fantacy (aka Dandelion)

  3. Very interesting! We've only purchased one 50 pound bag of DE and have used it for almost a year. (Wonder if it goes "stale"?) I even gave some to my Mom, but we still have at least 1/2 bag left. We sprinkle the run and coops with DE to help minimize SMELL. It does seem to help! LOL I think I'll discontinue it. Warnings to go breathe it in for humans or get it in our eyes has always made me a little leary of using it. What about our hens (and ducks) who are LIVING in it and much closer to the dust?

  4. Questions from a newbie backyard chicken keeper: I was hoping DE was a good way to worm my hens . . . do I need to worm my hens? How do I do that? How do I know the hens need to be wormed? They free range for a few hours each morning and again in the evening in Mid Missouri. My Buff Orpington has a dirty behind and loose stools.

    1. This is another issue that The Chicken Vet has addressed for us. You can read his info on worming here:

  5. Thanks for the info. I was leery about buying some, but it claimed to help so many things that I was almost convinced. I'm glad you found some experts to weigh in on the subject. I will be saving my money for chicken treats instead!

    1. J Brown, I'm sure your hens will enjoy your spending preference. :)

  6. Great info! I was wondering about DE for my chickens, but hadn't moved ahead with it. I think my girls will be fine without it!


    1. You will be able to tell if somthing is wrong with them by their behavior and appearance. Watch for changes in appetite, droopiness, feather damage, a drop in egg production, etc. It's best to check the base of their feathers regularly, particularly their vent and tail feathers, for mites, lice and signs of them like reddened, scaly skin and eggs.

      The internal parasites (worms, in particular) are sometimes visible in the droppings when the infestation is really bad. Chickens can handle a certain amount of worms but it can get out of control and then there are health consequences.

      That is totally the Cliff Notes version of the short answer. What I recommend is that you purchase several books, including: Gail Damerow's "The Chicken Health Handbook" and "The Chicken Encyclopedia," both of which are invaluable resources to both new and seasoned chicken keepers. There is also a downloadable book entitled "Raising Chickens for Dummies," which you can find by a Google search very easily. That can be read immeediately and is free. All of those books will be helpful to you in answering questions that will pop up over time.

      Your question is enormous and would take several blog posts to answer. What I recommend is that

  8. Thanks for the information. I bought a bag about 3 months ago and have been using in some. I will be watchful and give this some thought.

    1. Thank you for stopping in and for your thoughts, Charlotte!

  9. I have read such positive things abt. DE but nothing that was a FACT. It was written with alot of "may"s & "might"s. Externally I could maybe believe it might do SOMETHING in a dust bath. I was a little more skeptical abt. the internal part. Common sense made me doubt any claims of it's effects because once eaten by a chicken it would become wet. Thanks for giving us the facts & not a bunch of mights. I don't need to add DE to my shopping list.

  10. Wow thanks for such an informative post. You have given me much to think about and I do worry more about me, dusting it around than the benefits to the chickens. I wear a mask but just a simple one.

  11. (from Alexis Henry) Great info! For me there is not enough positive medical info. Too many maybe's and speculation. And if it's recommended that I wear a mask, then my girls should and I think it would be hard to find 30 mini hen face mask (my neighbors would get a great laugh though!)

  12. Kathryn Scherer10/28/12, 11:41 PM

    I face my birds toward the prevailing breeze while applying DE by hand to the undersides of feathers and to vent areas as well as legs-feet. This blows the dust away from their face and toward me, the applicator, who is wearing a dust mask. I find DE effective for mites.

  13. DE is amorphous Silica and is not harmful. 

    Crystaline silica of 1 micron or more may be carcinogenic.

    Diatoms are living organisms and the natural food for fish in lakes and oceans, so their shells are not harmful to humans.

  14. Everyone has a right to their own opinion, and you can express it without being rude! Kathy is anything but uneducated, and I find it humbling for her to ask other qualified experts opinions in addition to her experience. Maybe you don't agree with her in this particular instance, but you shouldn't dismiss her blog over one subject! I have owned chickens for 10 years and have been pleasantly surprised with all the information and creative ideas she has, because I don't know everything, but it sounds like you do!

  15. As I am starting a new flock of Orpys this spring this was timely information. My neighbors chickens suffer from lice and I expect to have to deal with the issue almost as soon as I move my girls outdoor to their "grown up" coop. Thank you!

  16. Trisha Freitag5/11/13, 3:50 PM

    I've been using DE with my hens for 5 years. I've only had to worm them one time and they've never had mites or lice. I mix it in their food at 1# per 50# (2%) - outside, before I put it in the storage bins, sprinkle it on the floor under the bedding when cleaning the coop, and I've never had a problem with it. However, if the birds ever got sick, I wouldn't hesitate to treat them with whatever seemed to be appropriate. I guess it's different for all of us. I'm hesitant to dismiss anything just because there's no documentation for the positive when the results of people I know personally are so good. Again, though, it's different strokes for different folks!

  17. Blanche Marie Couture8/22/13, 6:01 PM

    I do not give a rat ass about what experts have to say, most of the time they work for a corporation and what they say is mostly lies so people would get scare and buy their crap.

  18. I needed to hear this...thanks!

  19. TheChickenChick10/18/13, 10:25 PM

    My pleasure.

  20. Debbie Cernoch10/19/13, 9:58 PM

    I just bought a 20 lb bag of DE, glad I read about it. I thought it was good to rid ants and for adding to their dust bath. Also have read other articles good for worming. Since I read this, I'm not going to use it. Don't won't to take a chance in them getting sick from it. Thanks for your directory. It helps a lot. I go to it a lot and read them.

  21. TheChickenChick10/19/13, 10:10 PM

    Thanks Debbie, I'm glad it helped!

  22. Janet Pesaturo11/11/13, 8:07 AM

    Hi! I arrived at this post via another one that you contributed to the Clever Chicks Hop this week. I found it very interesting. I purchased DE once several years ago and sprinkled it in the litter hoping to prevent parasites The dust was so fine that I found it uncomfortable just to go into the coop. I couldn't wait until it was time to clean it out again. I never used DE again. I researched it and found exactly what you say here: no convincing evidence that it's effective against parasites. I also figured that if it was hard for me to breathe with DE in the air, it wasn't good for the lungs, avian or human! Now that I know it is mostly silica, I agree that it is likely to be a respiratory hazard. Silicosis is a known occupational lung disease.


  23. This article would be better if it were true.
    Food grade DE is made from AMORPHOUS DE, while non food grade is made from crystalline silica, also found in quarries, and *sand*.
    Perhaps you should better check your sources out, because this article only shows their (and your) ignorance.

  24. The last person who wrote, it was 2 years ago. I'm not sure someone will read me.I want to say that I have not been convinced at all by the article. I want to tell you why.
    First, the doctors do not have a lot of information about natural products. They know about the medicines that they have been taught about. So, they are not people who should be considered as experts because they are only experts in the usual medical stuff that are taught.
    Second, what counts is not opinions, it is the facts, I agree on this. So reading a comparison with sandblasting is completely an opinion. It is a way to understand that he has. This is not a fact.
    If someone does not trust in something because it does not seem true, this does not mean that it is not true.
    I can see that this doctor does not seem to have understood how diatomaceous works. And it is clear that he has not put to the test the product. You see, a fact is something that has been put to the test. The result is something that can be observed. So before having an opinion about something, one must be careful. If you don't believe that it can get rid of parasites, you need to put te product to the test and after you observe the result, you have a fact.
    Why do you think some big companies are now starting to make products for the gardens against bugs containing diatomacious earth? because it works.
    A fact is, for example, when you have a dog with fleas and ticks and you put DE in the fur of this dog. Then you see the next day a bunch of dead ticks in his bed. Then 2 or three days after the treatment, the dog has no more fleas or ticks. This is observable, it is a fact. It does not matter if you even understand how it works, even if it doen't make sense from your point of view.
    And what about internal parasites? Same thing. Put it to the test. Give the animal DE for a month and check. Then you have a fact.
    You should not be convinced by what I just wrote. You should put my explanations to the test... opinions are Worth nothing if they are not based on facts.

  25. Where did you read any facts ????? About de no test results not one test ?? Are u a real chichen vet ??.and did u know there are 100 of de on the market no de is the same so plz get your FACTS up to date thanks k

  26. Thank you! I just threw some out on my new coop and hens...this will be the last bit I use.

  27. DE Defender4/22/14, 9:02 PM

    First the benefits are wide ranging cause the DE at the feed store also had Calcium Bentonite Clay. Try killing scorpions naturally without DE and see how far it gets you. Don't breathe it in it is bad for you, don't over do it a little goes a long away and too much goes nowhere. Your chickens will not develop lung issues in their lifetime. DE is Non-Toxic. I can't speak for de-worming as I'm trained in structural pest control, but many older people will tell you they used to add it into the pancake mix back in the day. So use it to prevent mites from getting a foot hold, use it for the extra calcium in their diet. Don't be scared or a non toxic product just cause its a respiratory irritant.

  28. Ashleigh Reed Fitzpatrick4/23/14, 3:33 AM

    When I tried using this in my silkies' dust bathing area, they all developed a severe respiratory irritation that led to an upper respiratory infection. That's 16 silkies; 2 were babies and had to be euthanized. I've sworn off DE since. I am sharing this on my FB page, Flock of a Southern Chick and in The Chickenistas FB group. =)

  29. TheChickenChick4/23/14, 9:44 PM

    Thanks for sharing, Ashleigh. The misinformation circulated about DE in the poultry world is unfortunate at best.

  30. John Strifler5/5/14, 2:25 PM

    I dont have my chickens as of yet. I have a week long dry spell in the forecast. I plan to use the DE prior to my chikens arriving only as an added measure to kill off the last remaining fireants. I have tried every known remedy from tuna mixed with baking soda, to commercial chemicals that never have worked yet I got suckered into it again. Since I wont have my chickens until the middle of june I am positive most of the DE should be washed away. Since I also have dogs I am making sure they stay out of the areas I use it in.

  31. FGDE is the only thing safe to use for baby chicks. I had a major mite problem and will not use chemicals on the food that I eat, my chickens and eggs. I used it outside with the wind blowing opposite of me. So far its doing good getting rid of the mites and I am still receiving eggs. I feel better knowing its safer for my girls and my family.

  32. Tony Gilnett5/17/14, 9:56 AM

    Just remember Asbestos was touted in the 40/50's with being a great product, They have pictures of them putting it in playgrounds all over instead of sand. I wonder how that worked out for us???

  33. Thank you chicken chick for all your invaluable advice, Im rather far afield (in sunny Spain) so sometimes it can be a bit complicated to follow your advice but it is nevertheless a great source of help :) from me and my flock :)

  34. Hi, I have been adding DE food grade fit for human consumption to my chicken food/treat cooked grains and kefir whey. I only add it when I notice poop stuck on the eggs. It always clears it up.

  35. Pesticides are not drugs. I think it gives a false sense of security by calling them something different.

  36. DE in chicken feed has kept the ants out. Additionally, my DE package listed silicon as a much lower percentage and many trace elements including many required for shell production (calcium, phosphorus, and selenium). Even if it doesn't deworm (we haven't had any worms in years of DE use), it provides nutrients the birds need in a form easy to administer (mixed into feed)

  37. Cheryl Ortiz7/10/14, 12:32 PM

    I use DE in the coop in-between cleaning over the droppings. and in the run if it has been rainy and its muddy. I use a mask for my self and the chickens are always out of the area. I use a strainer that I scoop out the de and sift it as low to the ground and over the area. It helps with the smell too! and as soon as I put it over the droppings the flies are gone. I will sometimes put it in with the food. but not on a daily bases. I have used it on some of my flowers in a duster. very small amount. Has helped with the beetles and red mite spiders.
    because of the DE being so fine I would never use were they dust bath.

  38. It all depends HOW the DE is applied. In my experience of using DE:

    Internally as a wormer it probably is no good as it becomes wet.
    externally in a dust bath or sprinkled around the coop it WILL cause respiratory problems (I have experienced this).

    make a slurry out of it (mix it with water, it will remain quite runny,
    much more runny than paint), then paint it on your coop with paintbrush
    making sure you get into all the nooks and corners and then after a few
    hours when it has dried you have created a totally inhospitable
    environment for red mite. They will slowly die off. And the best thing
    about a DE slurry is that it will lasts weeks after just one
    application, you don't need to keep reapplying it (probably 3 times per
    year is enough), and there is NO dust because it is wet when applied and
    when dried it sort of sticks to the perches and coop walls rather than
    floating around the coop. You only need a small amount of DE mixed with
    water to cover a large area of your coop. But the coop will look as if
    someone painted it grey.

    I had a huge red mite infestation, and I
    have only used DE Slurry, and now I only see red mite occasionally. It
    worked for me, so it definetly does work, as with most things, it's all
    a case of HOW it is applied.

  39. Great to hear your experiences, Nassar. Thank you for sharing! One thought: if the DE is being applied several times annually, then it is sloughing off the coop and mixing into the litter/coop environment generally, which has to be a concern for both the birds and the chicken keeper. Don't you agree?

  40. To some extent that may be true. But when made into a slurry I use a relatively small amount. About 3 small handfuls are enough to completely cover half the inside of 4 x 6 coop. Even less than 3 handfuls can be used. And I would only do it a couple of times a year in the warmer months when red mite are most active, as each time it can last up to about 2 and a half months. Also the slurry comes off only a tiny bit at a time over the weeks, so the dust is pretty much non existent, by the time a bit more comes off the old bit has dissapeared probably into the ground somewhere (I have earthen floor in my coop). In this way there is just not enough DE in there floating about at any one point to affect the chickens in a bad way.

    From my experience the slurry does not cause any problems, but DE on it's own like in the dust baths can cause problems.


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