The common red mite Dermanyssus gallinae are blood sucking ectoparasites that can infest chickens and turkeys. They can strike any hen house at anytime but especially during the warmer summer months. Our best advice is to keep extremely vigilant where these parasites are concerned. They can be quite difficult to spot as they come out at night to feed on your hen’s blood and hide during the day. We suggest a regular check of your birds under their wings and around their vents, however, this will not always reveal their presence as they don’t spend all their time on the bird.
We recommend entering the house after dark with a torch and looking around the ends of the perches and cracks where they might be hiding. You may see a grey dust-like substance, these are mites that have not yet fed. Once they have feed, they turn bright red and then dark red. If you squash them you will see a trail of blood. Alternatively, take a piece of white paper and swipe between the cracks and crevices – if red mite are present, you will see streaks of blood on your paper.
Low numbers of mites mainly cause irritation and annoyance to the chicken making it restless. However, large numbers of mites can suck enough blood causing anaemia in the chicken, resulting in a pale comb and wattles, weakness, dullness and reduced egg production.
The lifecycle from egg to adult mite is only seven days so it is important to keep checking on a weekly basis.
The mites can also crawl up onto human skin and cause irritation but do not tend to live on humans.
There are a number of products available for the birds and also importantly, their environment. Begin using the products early in the spring to try and prevent an infestation outbreak.
If, unfortunately, you find your chickens and house are infested then you will need to carry out some additional measures and further cleaning.
Firstly, your cleaning regime must be done on 2 to 3 weekends in a row; their very short lifecycle means they will return in 10 days if eggs remain in the house and they begin to hatch out.
Northern Fowl Mite
The Northern Fowl Mite (Ornithonyssus bursae) is an oval shaped mite about 1mm in size. Like Red Mite it starts off a pale grey colour and feeds on the chicken by sucking its blood turning the engorged mite a black/brown colour. This feeding irritates the bird leading to it laying fewer eggs and even losing weight. If the number of these mites is large enough then the chicken can suffer from anaemia characterised by a pale comb and wattles. The mites can also result in matted feathers.
The mite lays its eggs at the base of the feathers around the vent, these hatch after a few days and can lay their own eggs in as little as 12 days, allowing their numbers to build up rapidly under ideal conditions.
The most important difference between Northern Fowl Mites and Red Mites is that Northern Fowl Mites will spend their entire life on the chicken (they can only survive 10 days off a chicken).
Control is slightly different to Red Mite because you really need to concentrate on treating the chicken as this is where the mite will be found. You will not find them hiding away in cracks and crevices like the Red Mite.
Treating your chickens is very similar Red Mite control. Start by using Chicken Vet Mite powder on a regular weekly basis as a preventive measure.
If you still suspect presence of Northern Fowl Mites then you may need to seek veterinary advice and use an “off label” medication such as Ivermectin 1%. These drops are applied to the back of the bird’s neck but are not licensed for use in chickens. If being used on chickens that are laying eggs, your prescribing vet must advise a suitable egg withdrawal period. Note: The eggs from these hens must never be sold for human consumption.
Scaly Leg Mites
Scaly Leg Mites and Depluming Mites are two closely related mites which both belong to the genus Knemidocoptes.
The Scaly Leg Mite (Knemidocoptes mutans) is commonly found on older backyard chickens.
This mite burrows beneath the scales of the leg causing the damaged tissue of the leg to ooze with tissue fluid on which the mites feed. This burrowing causes irritation, raised scales and crusting. You will notice thickened crusty looking legs.
In the early stages of infection the affected bird will be no more than mildly irritated by the Scaly Leg Mites but as the scales become thickened and the mites cause more extensive damage the affected legs will become very painful.
It is important to note that it takes several months for the scales of the legs to become raised and consequently to heal again after treatment.
The Scaly Leg Mites are transmitted by direct contact with infected birds
Treatment of the Scaly Leg Mite involves killing the mites and softening the roughened scales.
Killing the mites can be done using Ivermectin 1% spot on drops but it is important to note that Ivermectin is not licensed for chickens and as such the prescribing vet needs to set an appropriate egg withdrawl period and if appropriate, a meat withdrawal period. Eggs from hens that have had Ivermectin 1% must never be sold for human consumption.
Dunking the legs into a jar of surgical spirit or methylated spirits twice weekly for 3 weeks will also kill the Scaly Leg Mites. Do not do this on legs with open wounds as it will sting. Smothering the legs in Vaseline will help to soften the scales on the leg and to suffocate the mites. Scales can take twelve months to heal and completely regenerate so be patient as it takes a really long time to see an improvement in your chicken’s legs.
Finally, we recommend you routinely wash the legs using baby shampoo and a soft toothbrush. This can also be used to soften the scales on the legs and aid recovery.
The Depluming Mite
The Depluming Mite (Knemidocoptes gallinae) is related to the Scaly Leg Mite and like its better known relative, is a burrowing mite. However, whilst the Scaly Leg Mite burrows in between the scales of the leg, the depluming mite burrows into the feather shafts particularly on the head, neck, back, belly and upper legs.
This burrowing causes damage to the tissue which oozes with a nutrient rich fluid on which the Depluming Mites feed. This burrowing causes irritation and pain to the chicken causing it to scratch and to pull out its own feathers. Severely burdened chickens will lose weight and will lay fewer eggs.
One interesting fact about Depluming Mites is that rather than laying eggs, they give birth to live young and they can complete their lifecycle in as little as 17 days. They tend to be most prevalent in spring and summer, with numbers falling in autumn.
Stressed birds will allow their numbers to increase more rapidly. The mites can only be transmitted between birds by direct contact.
reatment for Depluming Mite involves using Ivermectin 1% spot on drops. But again it is important to note that Ivermectin is not licensed for chickens and as such you should always seek advice from your prescribing vet and apply the appropriate egg withdrawal period. Hens that lay eggs should never have their eggs sold for human consumption after treating them with Ivermectin. Treat the house as you would for Red Mite infestation.
Chickens can also suffer from Lice (Menophon gallinae) which are golden in colour and are approximately 1-3mm in length. These lice are relatively fast moving, they lay their eggs (nits) which are white, and both the nits and the lice can normally be found aruond the vent, under the wings or at the base of their feathers.
The lice bite the chicken and feed from its skin and also the fluid which oozes from the damaged skin. Low levels of lice only cause mild irritation but large numbers lead to weight loss, restlessness and a reduction in the numbers of eggs laid.
They tend to rapidly increase in number around the autumn and winter. Lice only live a few days and are often transmitted by direct contact.
The best way to treat them is to either use Ivermectin 1% drops. Please note this product is not licensed for use in chickens. You should always seek veterinary advice and if your bird is in lay your vet will need to prescribe an appropriate egg withdrawal period. For low burdens, use diatomaceous earth Chicken Vet Mite Powder. Treat the house as you would for Red Mite infestation
Ivermectin is an anti-parasite medication, effective against most worms (not tapeworm), mites and some lice including scaly leg mite and northern fowl mite. Ivermectin pour-on / drops is applied to the skin.
Ivermectin Drops are usually sold under the Small Animal Exemption Scheme for use in rabbits, Guinea Pigs and ornamental birds. Products licensed under the Small Animal Exemption Scheme are not licensed for use in food-producing animals such as chickens and it is for that reason that there is no information relating to the withdrawal period for eggs or meat following use of Ivermectin Drops on poultry.
Where there is a licensed alternative, vets will prescribe the licensed product. To treat worms – Flubenvet is the (only) licensed in feed product.
In the absence of licensed alternatives, veterinarians do sometimes prescribe this product for poultry under their own clinical judgment to treat lice in poultry.
It is however only a veterinarian who can advise on such use and it would breach of the veterinary medicines regulations and NOAH code of practice by supporting, or encouraging the use of this product on a non-target species.
Uses: Sometimes prescribed by Vets to treat endoparasites (worms) and ectoparasites (lice and most mites including scaly leg mite). Remember red mite live in the house, so housing will require alternative treatment.
Formats available: Injectable, oral or drops for skin. Pour on drops are usually prescribed.
Dosage: For the treatment of an existing infestation, repeat doses are required often weekly three times.
Egg Withdrawal period: As advised by Vet, depends on the strength of solution. Vets prescribing Ivomec Eprinex usually advise 7 days.
Slaughtering for meat for human consumption: As advised by Vet, depends on the strength of solution. Vets Prescribing Ivomec Eprinex usually advise 28 days.
Storage: In original packing below 25ºC and out of reach of children.
Wear gloves and wash hands thoroughly with soap and water following treatment.
The information given here is the opinion of the authors and should not be considered as professional advice. Where there is conflicting information, you should always follow the advice of your vet.
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