UC IPM recently held a webinar focused on pests affecting backyard chickens, featuring Dr. Amy Murillo, an Assistant Professor at the University of California Riverside who specializes in veterinary entomology. During the session, Dr. Murillo addressed questions from attendees about common ectoparasites and methods for managing them.
The pests discussed included lice, northern fowl mites, poultry red mites, scaly leg mites, and sticktight fleas. Dr. Murillo explained that these pests are not significant disease vectors: “None of the pests covered in this webinar are important vectors. Pests covered were lice (general louse), mite (northern fowl mite, poultry red mite, scaly leg mite), and flea (sticktight flea).”
Ectoparasite infestations can impact egg production in chickens. “Egg production can be negatively impacted by ectoparasite infestation,” said Dr. Murillo.
When asked if parasites remain after a catastrophic molt, she noted that it depends on the species: “It depends on the ectoparasite species. Most lice and northern fowl mites will be shed during the molting process, reducing overall infestation levels. Sticktight fleas and parasites that live off the host are unlikely to be affected by molting.”
On mite biology and behavior, Dr. Murillo stated: “An adult northern mite will live a couple weeks off host. An adult poultry red mite is likely to live weeks to months off host.” She added that temperature influences activity: “Yes, but it does depend on which species you’re talking about. We find that northern fowl mites…are negatively impacted by hot weather; their populations crash in the summer. And the opposite is true for poultry red mites which are more active in the summer and less active in the wintertime.”
Dr. Murillo also provided advice on prevention and sanitation practices to minimize contagion between flocks: “Visiting multiple flocks on the same day could potentially move ectoparasites from infected to uninfected flocks.” She suggested filling cracks or crevices with caulking if they might harbor mites but did not have specific bedding recommendations.
Bathing chickens was discussed as well: “Bathing chickens with water should be used sparingly to remove ectoparasites…It should only be done if the weather is warm or hot so the birds can dry quickly.”
For dust bathing and diatomaceous earth (D.E.), Dr. Murillo advised using only food-grade D.E.: “No, only food-grade should be used around animals and people…” Regarding potential harm from D.E., she said: “When we were testing it…we didn’t see any negative signs or anything indicating that it was harmful to them…you should check with your veterinarian.” The recommended mix for dust boxes is a 50-pound bag of sand with six cups of D.E., using washed play sand for its texture.
She explained how often D.E.-based dust baths need refreshing: “Average 4 to 6 weeks…What I found is the D.E. doesn’t go bad, [but] chickens kick it out of the box.” Wet D.E., according to her experience, remains effective at a microscopic level.
Sanitizing coops involves emptying and washing dust boxes with soap and water: “Yes [this will kill ectoparasites], if there are any ectoparasites alive after emptying the dust box.”
On chemical pest control options such as pyrethrins or Exzolt medication for poultry red mite management, Dr. Murillo emphasized reading product labels carefully regarding withdrawal periods for eggs: “That’s going to vary depending on the product that’s being used…You should always read the label when you are using any kind of pesticide product…” She also noted no withdrawal period is required for Exzolt but advised consulting a veterinarian.
Alternative controls like diluted dish soap may help reduce environmental presence of poultry red mites through cleaning nest boxes.
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For further information about managing chicken pests or related resources offered by UC IPM visit ipm.ucanr.edu.