What is Ivermectin?

Ivermectin pour on is a lipid soluble medication, derived from Avermectin for treating parasites including worms [except tape worm] and mites in chickens.

It’s usage however for chickens is ‘off label’. Meaning it’s use within chickens is not what it is directly prescribed for.

Its primary usage is for cattle and horses, but is also prescribed for usage in small birds like parrots and rabbits as a pour on solution.

Despite being ‘off label’ for chickens it is readily bought ‘over the counter’ and used effectively to treat a variety of illnesses.

In order to say if Ivermectin administration on chickens would help or cure illness we have to firstly examine the illness itself. Incorrect diagnoses of illness and therefore incorrect treatment can lead to mites or worms building up a resistance to such treatments, proving them ineffective at a potential later date.

Ivermectin Dosage for Chickens

Ivermectin Pour on For Chickens 

N.B if using Ivermectin to treat mites, as it is also used ‘off label’ to treat worms, it is suggested that you cease using any other worming medicines alongside of it. Always seek professional advice.

In the US & Australia

The same brand Ivermectin isn’t sold in the US or Australia as it is, in the UK.

The dosage for ‘Noromectin Pour On for Cattle’ made by the brand Norbrook is seen below:

ivermectin dosage for chickens

You therefore have to use the guidelines set by the manufacturer. Which are 1mL for every 22lb of body weight. That’s 0.045ml for every lb the chicken weighs calculated as (1(ml)/22(lb)).

Therefore a total solution of 0.36ml is required for a chicken weighing 8lb.

A drop is measured at 0.05ml. So to calculate total drops you divide the total amount required for one chicken (0.36ml)/0.05(drop measure) giving you 7.2 drops. These are my calculations and should not be taken as individual advise.

Found on Amazon here

This comes in a plastic screw top bottle. If you want to administer Ivermectin in drops you will be required to decant a small amount into another bottle capable of producing drops.

My calculations cannot be applied to any other brand of Ivermectin, other than two quoted above in the link. As strength varies amongst manufacturers of Ivermectin as does the administering of it [oral, topical or injection].

In the UK

Ivermectin is sold on Amazon here


The dosage label claim is 1 drop for every 500g the chicken weights. A mature leghorn chicken weighs on average 3.5kg (7.72lb) or 3500g.

So the dosage would be calculated as 3500/500 = 7. Therefore the total drops for an average weight leghorn chicken would be 7. This is an example and should not constitute individual advise for any chicken(s).


Follow manufacturers advise, which is usually, apply the correct dosage directly onto the skin on the back of the neck.

Ivermectin Side Effects in Chickens

Ivermectin use can cause the following side effects in chickens:

  • Diarrhea
  • Blindness
  • Abdominal Swelling

Alternatives to Ivermectin

Natural treatment for worms in chickens

Garlic is a fantastic natural treatment for worms in chickens. Placing garlic cloves into the water can help prevent worms, because garlic is high in sulfur.

Sulfur and potassium nitrate are two key ingredients found within worming treatments. Garlic has many other benefits including being anti-microbial and is high in selenium.

Apple Cider Vinegar is reported to dramatically improve gut and general well being within chickens read more about Apple Cider Vinegar here it includes the best mixing ratio to water.


Using Ivermectin to Treat Mites

Chicken mite

[Dermanyssus gallinae]

Most commonly referred to as Red mite, Roost mite or Poultry mite. These are bloodsucking mites that will bite not just chickens, but people as well. They are rarely found within commercial caged hens and more commonly found within farms with smaller flocks.

Chicken mite characteristics

The mites are nocturnal feeders that hide during the day, so are most commonly missed by visual inspections of chicken coops, which is why you have to be vigorous and vigilant. Vigilance should be most adhered to during the warmer summer months as that’s when they develop the most rapidly.

Where do they live?

They most commonly hide on roosts, under chicken poop and within the cracks of the coop where they lay their eggs. Whilst the life cycle of the mites are only 1 week, a chicken coop or infected area could remain infested for 6 months, even after the birds have been removed.

How does it spread?

Transmission of chicken mites is by mite dispersion along with contact from other infested birds.

What are the effects?

Heavy infestations of chicken mites will decrease egg production within hens and cause possible limited reproduction amongst males. It also reduces weight gain and development within young chicks. In serious cases it can cause anemia and sadly death.

What can you do to prevent it?

Using good sanitation practices, regular cleaning of the coop, changing of the chicken nest box ‘bedding’ and regularly changing of the floor bedding.

Using a pressure hose would aid ‘getting into the cracks’. It would also be seen as prudent to isolate a new chick or chicken for a number of days, to examine for signs of mites, before introducing them to your flock.

How else can I treat Chicken Mite? [other than Ivermectin]

Control of the infestation can be achieved by dusting or spraying the birds and the litter with carbaryl, amitraz, malathion or coumaphos.

Carbaryl is commonly sold as the ingredient of ‘Sevin Dust’ and is widely reported as working well to combat chicken mite amongst other unrelated issues like ant infestations and fleas. Sevin dust is typically 5 percent Carbaryl. However egg withdrawal could be an issue after using Sevin, always read the label.

Malathion is most commonly found in insecticides but usually in liquid form.

Miticide treatment in a spray form is best used on the feathers in the vent area, as a spray will have sufficient force to correctly penetrate this area to treat the afflictions.

Miticide is commonly found in multipurpose bug killer and is commonly used within organic gardening.

Permethrin is initially active but has meager residual killing power. Permethrin is often marketing as ‘Garden and Poultry’ dust by brands like Prozap is ordinarily sold within poultry supply stores.

Lastly, ‘inert dusts’ can be very effective but application rates need to be high if humidity is high. Inert dusts include diatomaceous earth which is well known amongst backyard chicken enthusiasts.

Most diatomaceous earth products come with an applicator for ease of use. The highest quality diatomaceous earth is generally regarding as being ‘pure and 100 percent fresh water’.

These will only work if the parasites have not built up a resistance to the mentioned chemicals.

Cleaning of the coop when infestation occurs

Common areas would include, the chicken run and areas where chickens will individually ‘clean’ themselves such as a ‘dust bath’. Also the underneath of the coop and ground below, if any, should be sanitized too for best practice.

To apply the dusts into the cracks and ‘hard to reach areas’ a fan could be used to blow the dust into the affected areas.

If you plan to use Dimethoate and Fenthion to sanitize the coop and other common areas, do so when chickens are not present.

If using any of the treatments mentioned, the user, should take appropriate action to negate risks such as direct contact with harmful chemicals, breathing in dusts or allowing it into the eyes. Follow the guidelines set by manufacturer.

Feather Mite

[Syringophilus bipectinatus]

Surface feather mites do not feed on blood, but skin scales, fungi/debris and the oils that the feathers produce naturally.

There are over 25 different species of mites but cases in domestic poultry are relatively rare. Syringophilus bipectinatus is the species found in chicken feathers globally, but there are 3 species of feather mites that live in chicken quills in Europe alone.

They do little damage but could reduce egg production due to feather loss and dermatitis. This uncomfortable illness within chickens can cause them to stop eating and as such cause mal nutrition.

‘’Affected birds can be applied with topical or oral ivermectin or dusted with pyrethrin or carbaryl powder’’ Source the MerekVetManual.com

Depluming Mite

[Neocnemidocoptes gallinae]

This mite is also found worldwide. During spring and summer it burrows into the epidermis which is located at the base of the feather shaft causing a penetrating irritation to chickens. As a direct result due to the burrowing of the mites, the chicken can suffer from skin lesions, digit necrosis and hyperkeratosis, which is a thickening of the skins outer layers.

‘’Birds affected with this need to be isolated and treated with Ivermectin, Sevin dust or Malathion.’’ Source the MerekVetManual.com


Northern Fowl Mite

[Ornithonyssus sylviarum]

Northern fowl mites are blood sucking parasites that have a life cycle of around 7 days and that time is generally spend on the host [the chicken].

When off the host, mites are thought to live as long as 2 months, this however is largely dependent on temperature and relative humidity. Northern fowl mites are also reported to be found on turkeys, mice, rats and even people.

Newcastle disease virus and fowlpox virus have been isolated from northern fowl mites.

The mites are located on eggs or found by parting the feathers in the vent area. Visual indicators in the vent area could include, but are not limited to: soiled feathers, severe scabbing and crusty thick skin.

For control and treatment of northern fowl mites refer to chicken mites in the above section.


Tropical Fowl Mite

[Ornithonyssus bursa]

As the name suggests it is distributed across the warmer regions of the world with reports of these mites occurring in areas such as Hawaii, Texas, Florida but also in New York. It is very similar to the northern fowl mite in resemblance, habits and in its biological make up. The main difference being that the tropical fowl mite lays a greater proportion of its eggs in the nest.

For complete treatment see and follow advise for chicken mite, found above.


Scaly Leg Mite

[Knemidocoptes mutans]

It is a spherical sarcoptic mite, aptly named as it tunnels into the tissue under the scales of the legs.

This usually only affects older chickens, which suffer from leg irritation and thickened, encrusted leg scales. Both the feet and leg scales rise up, often resulting in immobility as it’s uncomfortable for chickens to move.

Because of this chickens stop feeding and if untreated, after several months they can die.

Not always just limited to the legs and feet, the mite may attack the comb and wattles too.

The entire duration of the mites life is spent within the skin and the spread of one affected bird to another will occur when there is contact made. The mite enters a domestic chicken flock typically from contact with wild birds.

Infections of Knemidocoptes mutans can remain dormant for some time, what triggers the mites population to increase is stress.

Chicken coops and common areas should be treated as per the action taken for chicken mites, please see above.

For more information on Scaly Leg Mites view our dedicated page.

Cyst Mite

[Laminosioptes cysticola]               

The cyst mite is a small parasite that causes caseocalcareous nodules. Visually this can be observed as the death of cells and the skins tissue turning into what is described as a soft cheese like substance.

Ivermectin could be effective as a treatment and it stands a better chance of be an effective cure if the bird has no prior usage of it, ie it hasn’t built up a resistance to medication. Destruction of the birds is usually the best control measure.

Ivermectin for treating Worms in Chickens

Again being off label there unfortunately is no literature available relating to the exact dosage of Ivermectin for treating endoparasites [worms] within chickens. Only a blanket dosage policy for birds such as parrots or pigeons. However people use that guideline as a bench mark. Fortunately most manufacturers provide a dosage based on the weight of the animal.

Egg & Meat Withdrawal

Withdrawal refers to the duration after the Ivermectin treatment has ceased, where the meat or eggs from the affected chicken is not fit for human consumption. Also referred to as ‘depleted drug residue’. On the issue directly relating to Ivermectin F.A.R.A.D states:

‘’ Depletion of Ivermectin residues in the eggs of treated hens has been investigated in only a couple of studies. Given the limited studies and data available, FARAD cannot provide a blanket withdrawal interval recommendation’’

Therefore in short there are no guidelines on withdrawal for chickens after using Ivermectin. Some manufactures of Ivermectin do state that egg withdrawal should last 7 days.

Natural Treatment for Scaly Leg Mite

This includes soaking the chickens legs and then applying an oil, like Olive Oil, then applying a heavy spreading of petroleum jelly over the top of that. Vaseline is a petroleum jelly brand name most accessible to people. The jelly should be reapplied daily for several weeks.

This is covered in detail, on our Scaly Leg Mite Identification and Treatment Page.


Article References:





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