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 concerning reports of the carcinogenic effects on humans breathing crystalline DE and the manufacturers’ warnings to wear a respirator when using food grade DE (which is primarily amorphous DE, but also contains the more dangerous, crystalline form).
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).
Whenever I have technical or scientific questions, I defer to trained, experienced, respected, experts for guidance. In deciding whether to use DE in/around/with/on/near my backyard chickens, I looked to several highly respected experts in the poultry 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. Please also read about the dangers of DE from an experienced, well-respected herbalist in a separate article on my blog, which can be found HERE.
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.”
In The Chicken Health Handbook, 2ed, Damerow states, “Some types of respirable dust physically stick to lung tissue…(r)espirable particles of diatomaceous earth is an example of dust that sticks, causing scar tissue to form that impairs respiration.” (pg. 158 emphasis added)
I also asked Dr. Mike Petrik, DVM, MSc, aka: The Chicken Vet, for his thoughts about DE. He is a practicing veterinarian who works with professional farmers and has overseen the care of millions of laying hens in his practice. What follows is his written response.
“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 shop as the result of sandblasting old cars.