To use permethrin spray on chickens, you need to dilute a 10% permethrin concentrate at a ratio of roughly 1 part concentrate to 400 parts water, then apply about half a fluid ounce of that solution per bird as a fine mist. The process covers both the birds themselves and their living space, and you’ll need to repeat the treatment at least once to catch newly hatched parasites.
What Permethrin Treats
Permethrin is the most widely used chemical for controlling external parasites on chickens. It kills northern fowl mites, poultry lice, ticks, and bedbugs by paralyzing their nervous systems on contact. It works on adult parasites but does not kill eggs, which is why repeat treatments matter.
Mixing the Solution
If you’re working with a 10% permethrin concentrate (the most common form sold at farm supply stores under brands like Martin’s or Gordon’s), the standard dilution for poultry is 8 fluid ounces of concentrate per 25 gallons of water. That works out to roughly 1 part permethrin to 400 parts water. For smaller batches, you can scale it down proportionally: about 1 teaspoon of concentrate per gallon of water, or 2 tablespoons per 5 gallons.
Mix your solution in a pump sprayer that produces a fine mist. A garden-style hand pump sprayer works well for a small flock. Don’t use a sprayer that’s previously held herbicides, since residue could harm your birds.
Spraying the Birds
Each chicken gets about half a fluid ounce of spray solution, which isn’t much. One gallon treats roughly 100 birds, so a small backyard flock only needs a fraction of a gallon. Set your sprayer to the finest mist setting available.
The goal is to get the solution down to the skin, especially in the areas where parasites concentrate. Focus on the vent area (under the tail), under the wings, around the neck, and along the breast. Part the feathers with one hand while misting with the other. Lice and mites tend to cluster around the vent and base of feathers, so these spots need the most attention. Avoid spraying directly into the bird’s eyes, nostrils, or beak.
Treating chickens is easiest after dark when they’re roosting and calmer. Pick up each bird, hold it gently, spray the key areas, and set it back on the roost. Working with a partner speeds things up considerably.
Treating the Coop
Spraying the birds alone won’t solve a mite problem because northern fowl mites and especially red mites spend part of their life cycle hiding in cracks, roosts, nesting boxes, and coop walls. You need to treat the environment at the same time you treat the flock.
Use the same diluted solution to thoroughly spray roosts, walls, nesting boxes, and any cracks or crevices where parasites hide. Pay extra attention to the undersides of roosts and joints where wood meets wood. Do not let the spray contact feed or water containers; remove them from the coop before you start.
After spraying the coop, allow at least one to two hours for surfaces to dry and the mist to settle before letting birds back in. If you’ve removed the birds to spray, replace the old bedding with fresh material once the surfaces are dry. Contaminated bedding can harbor eggs and re-infest treated birds.
Repeat Treatment Schedule
Permethrin kills adult mites and lice but doesn’t penetrate eggs. Most poultry parasite eggs hatch within 7 to 10 days, so you need a second treatment about 10 to 14 days after the first to kill the next generation before they can lay new eggs. Some heavy infestations benefit from a third treatment two weeks after the second. Spraying every two weeks is the maximum frequency recommended on most product labels.
Check your birds between treatments by parting the feathers around the vent. If you still see tiny crawling insects or clusters of white eggs at the base of feathers, the infestation is still active and the next round of treatment is warranted.
Egg and Meat Withdrawal
Withdrawal periods vary by product. If the permethrin concentrate you purchased is labeled specifically for use on poultry, the egg and meat withdrawal times will be printed on the label. Many permethrin products labeled for poultry carry no egg withdrawal period, but you need to verify this on your specific product. If you used a permethrin product that doesn’t mention poultry on the label at all, contact a veterinarian for guidance on safe withdrawal times before consuming eggs or meat.
Protecting Yourself During Application
Permethrin is relatively low in toxicity for mammals but can irritate skin and eyes, and you should avoid breathing the mist. Wear long sleeves, long pants, closed shoes with socks, and chemical-resistant gloves (nitrile works well and is easy to find). If you’re spraying in an enclosed coop, a simple dust mask or respirator helps keep you from inhaling the fine mist. Wash your hands and any exposed skin with soap and water when you’re finished. Change clothes before handling food or touching your face.
One important note: permethrin is extremely toxic to cats. If you have cats that share space with your chickens or access the coop, keep them away from treated areas until surfaces are completely dry, and never let a cat come into direct contact with freshly sprayed birds.