Poultry Mites are external parasites that feed off your flock. These are serious as an infestation of some species can cause up to 6% blood loss on a single hen daily, leading to severe anemia and or even death. While mites are usually clumped into one category, there are technically several species of mites. I will focus on the most common mites in our area ( Western United States, specifically Utah). Recognizing the species that has made a home within your flock and reacting appropriately is essential.
Northern Fowl Mites (NFM)(Ornithonyssus sylviarum):
Signs: Birds may have thick, crusty skin, scabbing, dirty vent feathers, excess preening, decreased feed consumption, drop in egg production (up to 10%), and pale combs.
Identifying: NFM are roughly 0.5mm in size with 8 legs and a rounded, elongated body. They appear to be black or greyish in color. They are prevalent in cooler climates with a preferred temperature of 65-78 degrees Fahrenheit. NFM like to localize around the vent. NFM are species-specific, so while they may bite and cause irritation, they will not survive off other species.
NFM are considered haplodiploid. This means male NFM are produced from unfertilized eggs, and females are made from fertilized eggs. Unfortunately, this is terrible news for Backyard flock members as it only takes one female mite to be introduced to the environment, and she can lay male eggs to cause an expansion of the infection.
Life Cycle: There are 4 life stages. Eggs Hatch in 1-2 days, Larva molts after 8 hours, Nymphs take 4-7 days to molt into an adult, and an adult will lay eggs after feeding about roughly 2 days from transition. On average, the adult female will lay 2-5 eggs per feeding. All four life stages can be completed within 5-12 days. A single mite can live up to 3 weeks, meaning a single female can lay over 50 eggs, quickly leading to a large infestation. This entire life cycle will be completed on a host bird.
Survivability: NFM can survive up to 3 weeks off a single host. Field research has presented NFM to show drug resistance. In this case study, it was shown to have a 72% frequency resistance to permethrin.
Biosecurity Concerns: While they do not infest people or other animals, they can bite, causing irritation and, in some cases, allergic reactions. They are not known to be vectors of disease.
Red Mites (Dermanyssus gallinae): Often referred to as chicken mites and roost mites.
Signs: Resistance in your flock to return to the coop at night, feather picking, pale combs/wattles, and scabs or irritated skin. You can also see signs in the coop, including grey or red dust in crevices and tiny moving red or brown specks; you can also notice blood smears on eggs or perches.
Identifying: At only 1/50th of an inch in size, the red mite is close to the size of the period at the end of this sentence. They have a round body shape with 8 legs. Directly after feeding, they will be bright red to purplish in color. If they have not been fed recently, they will appear brown/grey. They reside off the bird, and you can generally find them in the coop, within the cracks or seams.
Life Cycle: The average life cycle of the red mite is 7-14 days. They have 5 life stages. Eggs hatch in 2-3 days, then after hatch, they are considered larvae. The larva stage lasts 1-2 days. Then molt into protonyphm for another 1-2 days, then transition into Deutonyphm. The Deutonyphm only lasts 2-3 days until they transition into an adult. After transitioning into an adult, they can begin laying eggs in 12-24 hours and reproduce for up to 6 weeks.
Survivability: Red mites are considered extremely hardy, able to live up to 6 months on average, and in proper conditions up to 9 months after feeding. Since they do not live directly on the bird and only feed every 1-4 days, they can be challenging to eradicate. Treatment may need to take place every 4-7 days until no more signs are present. Field studies have shown that up to 86% of red mites can be resistant/tolerant to carbaryl and permethrin.
BioSecurity Concerns: Red mites are considered enzootic. Research has shown that red mites can feed off of mammals, including humans and dogs. Although this does happen in low frequencies, it has still been documented. Another concern regarding red mites is that they are shown to be vectors (spread) of disease, including MG/MS, Fowl Pox, New Castle Disease, and some salmonella species.
Treatment Options
A few drugs on the market are labeled safe for poultry use.
Spinosad: The most frequently recommended pesticide would be spinosad. This is the active ingredient in the name-brand Elector PSP. The benefits to Elector PSP is that you don't have to wear protective gear to apply, it can be applied directly to the birds and the coop, it is an adulticide and larvicide (the only one on the market), and there is no egg withdrawal period after application. Some research showed a decline in mite populations up to 77 days after application. PSP has no cross-resistance when used in conjunction with permethrin.
Spinosads have a delayed interaction with arthropods, so immediate death typically does not happen. Increased mite mortality can be seen 2.5 hours after application and up to 2 weeks after that.
Permethrin: Permethrin is another pesticide rated for poultry. Permethrin is the synthetic form of pyrethroids that allows for longer environmental usage. Permethrin does not have an egg withdrawal period and is considered low toxicity to most mammals. There is an exception as it is highly toxic to cats while wet. Permethrin is an adulticide, meaning it will only treat adult mites and must be reapplied every 7-14 days to clear an infestation completely.
Ivermectin: Ivermectin is considered off-label for poultry. It can also be used to help control mites, but it is important to note there is an 8-week egg withdrawal period after the last application of Ivermectin. Since this is not treating the environment, it is typically used in conjunction with sanitation and another pesticide to clear red mite infestations.
While DE and other powders are sometimes recommended, I personally do not, as they can cause respiratory distress for the birds and caretakers alike.
How to prevent/limit exposure:
Wild birds visiting your poultry waterers and feeders are the most active vectors of poultry mites. Just one wild songbird visiting can cause an infestation within your flock.
Other vectors include rodents, humans, and uncleaned equipment.
Limiting access to your poultry areas to visitors and pets can help decrease the chances of mites migrating.
Having a vaccination protocol in place for your local area can help keep your flock's immunity up and help prevent secondary infections if they become ill with mites.
Research has shown that ectoparasite resistance is a genetic trait. If you plan to breed and maintain your breeding flock, detailed records and proper culling, you could breed/raise birds with a higher tolerance to parasites like mites and lice.
It's essential to closely monitor your birds and inspect them regularly so infestations can be caught early.
Comentários