For those experiencing problems with red mites and/or feather lice who do not wish to use pesticides or other chemicals in treatment (particularly backyard chicken keepers or those with smaller flocks):

Several years ago, during the hottest, most humid time of year, we experienced a MASSIVE red mite (and feather lice) infestation - the moment I touched the coop door, armies of the buggers would swarm onto me and I'd be itching for the rest of the day. Online sources noted that diatomaceous earth (DE) would not be sufficient to tackle such a heavy infestation but a friend who had once used DE to rid her entire yard of dog fleas recommended I try it anyway.
We have 2 chickens in a 4'x9' coop and run (a relatively small amount of space that needed to be de-mited which likely factored into the DE's success) but we managed to kill all our mites and lice within two weeks using DE. The feather lice were gone after only a few days and after a week of continued use, only the biggest, hardiest mites remained alive. After two weeks, our coop was pest free and has been ever since.

Killing an infestation with food grade diatomaceous earth (from personal experience):
  1. After an infestation has been identified, find a week with no rain to begin the de-miting process.
  2. First clean out all bedding and droppings in the chicken house and remove all accessories (roosts, ladders, etc.).
  3. Rinse down coop and accessories (garden-type power hoses work fine) twice and wait for it to dry.
  4. Mix a bowl with 1 part water and 1 part DE to make a DE paste. Grab an old paintbrush and paint the walls of your coop, roosts, nesting boxes, doors, ceiling, roof, accessories and anything else you can with liberal amounts of paste. Make sure you get it into all the cracks as well, as this is where the mites like to hide. Once the paste dries, all your surfaces will be covered with a nice layer of DE, forcing the mites to walk through it. You can now put all your accessories back in the coop but do not replace the bedding yet.
  5. Throw/dust liberal amounts of DE onto anything in the coop that could not be covered with the DE paste such as the dirt in the run. Make sure to rub an extra layer of DE onto the roosts to guarantee that mites trying to reach your birds at night will be covered in a thick layer of DE. Sprinkle DE in the area immediately around the coop as well. Be generous with the DE - You don't need to dump a 20 lb box in one square foot, but I swear my neighbors thought it snowed in our chicken coop by the time I was done dusting. Some people recommend using a sieve or a sock to spread DE evenly on the ground but sprinkling with your hands works just as well if you don't have an extra sieve or sock.
  6. Dust your birds with DE by gently rubbing DE in their feathers. Make sure the dust gets all the way to the feather shafts at the skin as this is where the mites and lice hang out. Dust every part of your chickens, including tail, leg feathers, and tops of their heads but avoid getting it on their face or in their eyes noses or ears. Being thorough is critical - leave 1 patch of feathers undusted or not dusted deep enough and the parasites will have a haven.
  7. After 3 days, clean out any poop or feathers that may have built up in the coop house and re-dust any areas of your coop where the DE has come off (usually roosts, floor, and run). Again, be generous with the DE. Then re-dust your birds to kill any new pests that may have hatched after the last dusting.
  8. Repeat this process every 3-5 days until there are no more mites or lice on your chickens or anywhere in the coop; then repeat it one last time for good measure. Now bedding can be added back to the coop. The lice should die pretty quickly after applying DE, as only mites are hard to kill. Do not be discouraged if there isn't improvement the first few days. The mite population should start noticeably declining after about a week and be gone or almost gone after 2 weeks. If after 2 weeks there is no improvement, then you may need to try a different treatment method.
  9. If it rains at any time during this, wait until the coop dries (DE cannot dehydrate buggers if it's already wet) and replace any DE that has washed away. Note that rain isn't always bad - we had heavy rains in the second week of our demiting that flooded the run of our coop, drowning the mites in the dirt or forcing them to climb into the DE covered coop. I did need to repaint the outside walls of the coop with DE paste and re-dust the run afterwards, but a good flood of the run and its surrounding areas did wonders for controlling the mite population, as it is usually the mites in the dirt that are hardest to kill.
To contain the spread of mites:
As we spread DE around the coop, we spend time in contact with the lice and mites and risk spreading them into our homes. Typically, feather lice aren't a problem as they eat only feathers and can't live for very long without an avian host, but red mites can and will infest humans. To minimize the chances of this happening,
  1. Apply a good layer of bug repellent (such as Off) to your hands, feet, arms, legs, and even gloves, shoes, and socks before you go out into your coop. Odds are, if the infestation is bad enough, some of the red mites will still crawl on your body, but much less so than if no insect repellent is used.
  2. If mites have spread to another part of your yard, you may need to sprinkle DE in that area as well to kill them (or if your climate is rainy like mine, avoid going in the area or letting your chickens go into the area until a good rain floods the area and drowns the mites).
  3. Go somewhere away from the entrance to your home and rinse off shoes and any tools used to kill mites after you are done using them for the day. Store them away from your home where any remaining mites will not come into contact with people or pets. Once you are fully done with the demiting process, clean these thoroughly before bringing them back into the house or garage. If you are not sure if all the mites are washed off and want to be extra safe, you can dust the tools with DE and leave it for a week or keep the tools away from anything with blood for a few months until all the mites have been starved. For your shoes, submerge them in a bucket of water and detergent for a day to drown mites hiding inside before washing and wearing them again.
  4. Hose off your arms, feet, and legs before you enter your house each time you come back from somewhere you could have come into contact with mites. Then wash your hair and shower thoroughly. Remember that mites like to hide in warm, dark, and moist places. Make sure your clothing is immediately and fully submerged in soapy water for at least a few hours before you wash them to drown hiding mites. Even if you don't think you have mites on you, it's better to be safe than sorry as mites are very hard to kill once they get into a home.
  5. If mites have indeed set up camp in your home, do not fear! There are still ways to kill them, although they may no longer be organic. Feel free to contact me for advice.
Prevention of future infestation:
  • Make sure the coop walls, roosts, and bedding always have a thin layer of DE on/in them to deter pests from moving in in the future.
  • Check chickens and coop regularly for signs of mites and lice (especially in the summer) and dust your birds/coop with DE if you find any before the problem grows into a full infestation. A good way to keep chickens mite free is to provide them a DE + dirt mixture to dust bathe in so they rub DE into their own feathers.
  • Keep feathers and poop from building up. After our mite infestation, we upgraded our coop to have a wire bottom beneath the roosts so droppings and feathers fall into a compost pile beneath the coop, making cleaning much easier. (Deep litter method does not work in our hot, humid climate and the extra ventilation helps keep our birds cool in our sweltering nights).
Safety:
  • Please make sure the DE is FOOD GRADE as only food grade is safe to use. For backyard chicken keepers with just a few birds, 10 lbs should be more than enough DE to last a long, long time.
  • DE is a nontoxic type of "rock powder" (so safe for pets and kids to be around) that works by slicing pests that walk through it and dehydrating them. Due to its dusty, dehydrating nature, wear gloves, goggles, and a mouth mask when handling DE to avoid skin/eye/lung irritation and avoid getting it on your skin or breathing it in. Otherwise, you'll be sneezing a bunch and have pretty dry skin for a while.
  • Do NOT give chickens a tray of pure DE to dust bathe in as they will be rolling in it and breathing it in which will make their respiratory systems very uncomfortable. Mix some DE into the dirt where they dust bathe instead.
  • I do not know how well chicks handle being dusted with DE, if any will be involved.
  • Remember to stay hydrated and work in the shade as much as possible in hot weather.
Update: I recently learned that EPA regulated pesticide DE is the safest for people and pets not food grade, as pesticide grade is more tightly regulated! Food grade is meh to use but pesticide grade is much better.

Hopefully, the DE method works as well for you as it did for us. B est of luck to you and your birds and feel free to message me if you have any questions :)
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