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External parasites

A parasite is an organism that lives on or in a host and gets its food from or at the expense of its host. The entomologist E. O. Wilson has characterized parasites as "predators that eat prey in units of less than one”. They are micro predators.

Today, we focus on the external parasites who live on our chickens and we will discuss internal parasites in a later article.

It’s important to detect the presence of parasites early before they cause severe problems. Always be on the lookout for them when you are in the coop cleaning, adding food and water, and collecting the eggs. You may see the bigger parasites who spend their day in the coop crawling around on the roosts and in the nests. Do you notice any change of behavior in our chickens? Are they restless and itchy? Are they hesitant to enter the hen house? Are they laying less eggs? Check your chickens often for parasites and their damage. The general symptoms of an external parasite infestation include anemia (pale comb and wattles), irritation, broken/chewed-looking feathers, feather loss, reddened skin patches, weight loss, low energy, a fluffed-up or sick appearance, and in extreme cases, death.

As with many things, prevention is better than the cure. It is much easier to get rid of a few parasites than an infestation.

  • Keep a clean coop. Dirty and uncared for housing and yard are an open invitation to rodents, flies, and parasites.

  • Practice good biosecurity. Do not bring in contaminated equipment, shoes, or clothing. Some parasites are microscopic and you can’t see them.

  • Perform regular health checks on your chickens, and quarantine all new birds before introducing them to your flock.

  • Exclude wildlife as much as possible, as both rodents and wild birds carry parasites.

There are so many insects (bedbugs, fleas, mosquitoes, lice, ...) and arachnids (mites and ticks) who feed on chickens that we will narrow our discussion to some of the most common mites and lice found in North America.

Let’s start with mites who are by the far the most common external parasite of chickens. They are tiny relatives of ticks and spiders. They are small, usually under 1mm, and may not always be visible to the naked eye. There are several species of mites. Some feast on blood, while others prefer skin or feathers. Some mites spend a lot of time off the bird, while others remain on the chicken’s body at all times.

The northern fowl mites are the worst. They feed on blood, stay on the bird day and night, and their life cycle is between a week and two! Although they are difficult to spot, their debris isn’t. Look for dark patches in the feathers and on the skin, especially around the vent area. Another sign of their presence is seeing little black dots crawling on the eggs in the nest. Contrary to most external parasites, infestations are generally worse in winter. It’s therefore really important to keep dust-bathing areas dry during the rainy season.

To get rid of these mites, you need to treat all your chickens and the coop. On the chickens, you can use an insecticidal powder, Ivermectin, or Finopril. See below for details on each product. For the coop, using an insecticidal powder is best.

The red mites, aka chicken mites, poultry mites, or roost mites, are the most common mites found in warmer climates. They live in cracks in the coop and are very difficult to eradicate. They come out at night to feed on the chickens. They complete their life cycle in ten days and are more active in summer. They can remain dormant for up to five months during the winter. To spot them, go with a flashlight at night and look for tiny specks crawling on the roost or on the birds themselves. Another telltale sign is if your chickens are reluctant to go in the hen house at night.

The best way to eliminate red mites is to move your chickens in a new clean coop and treat the old coop with an insecticidal powder or with oil (see below for details). It can take multiple applications over a month or two to effectively kill the mites. In the case of a very severe infestation, the only practical thing to do is to destroy the old coop.

The leg mites, aka scaly leg mites, live in the legs of the chickens. They burrow under the scales and eat the skin, leaving piles of debris behind them. The scales on the legs start to lift up and become painful and uncomfortable for the bird.

Fortunately, this mite is relatively easy to eradicate by treating the bird with Ivermectin, or covering the legs with petroleum jelly to smother the mites.

There are several species of lice who infest chickens, and they can be found on the same chicken at the same time. The lice feed on dry skin scales, scabs, and feathers. This irritates the chicken so much that she won’t eat or sleep well. She may become restless; she will scratch and peck her own body.

The body louse is the most common type infecting mature chickens. It is flat, straw-colored, and about 3.5mm long. It lives on the skin of the less densely feathered area of the body (below the vent, under the wings). They also move very fast. There are also the head louse, the shaft louse, and the wing louse who as their name indicates live on different parts of the chicken’s body. Lice lay their white/grayish eggs in clusters near the base of the feathers.

Treat the whole flock as soon as you spot lice on one of the birds. As with the mites, dust them with an insecticidal powder. You could also apply Fipronil topically. See below for details on the different products.

Let’s now talk about treatments. As we said at the beginning, many external parasites can be controlled through proper management. But once they get in, you will need to treat either the infected birds individually or the coop or both.

Applying an insecticidal powder is the most common way of killing external parasites. Apply the powder on the wings, saddle, tail, and vent area. Avoid the head, especially the eyes, and make sure you and the chicken don't breathe it. Check a week later and if some parasites are still around, repeat the treatment. If using it in the coop, dust the corners, the roosts, and the cracks. Wear a dust mask and goggles to keep the powder out of your eyes. As with any product, read and follow the instructions on the label. There are a lot of poultry dust products to choose from, here are a few:

  • Diatomaceous Earth (DE) doesn’t poison the insects, but kills them by dehydrating them. It’s effective against red mites, fowl mites, feather mites, lice, sticktight fleas, ticks and, bedbugs. Get food grade DE so no other type of insecticide is included. Because it’s not a toxin, there is no egg withdrawal period.

  • Pyrethrin and Pyrethroids (Permethrin) are approved insecticides for use in chickens, but they are highly toxic fish, honey bees, and cats. It’s effective against red mites, fowl mites, feather mites, lice, sticktight fleas, ticks and, bedbugs. They come in powder form or in concentrated liquid that can be diluted into a spray. There is no egg withdrawal period.

  • Carbaryl (Sevin) was traditionally used, but due to its high toxicity, its use is forbidden in California, and we wouldn’t recommend it to use anywhere else either.

There are also some other types of treatment:

  • Petroleum jelly (Vaseline) is used mostly to smother leg mites and sticktight fleas. Coat the area where the parasites are and repeat once a week until they are gone.

  • Oil (linseed, neem, or mineral oil) can be used in the coop, on roost, nest, cracks to eradicate red mites. It’s not toxic to the chickens.

  • Shampoo (any commercial pet shampoo) can be used to control many of the external parasites. It’s important to thoroughly soak the bird in warm water (up to her neck) and rub in the lather in her feathers, especially around the tail and vent area. Then rinse her thoroughly, dry her with a towel, and finally blow dry her. Never put a wet chicken outside, even during warm weather.

  • Ivermectin is actually classified as a drug and not an insecticide, it’s not approved for chickens who are considered by the FDA as “food animals” and very little research on egg withdrawal period has been done. However, it is quite effective against external and internal parasites and many people use it. It comes in different forms (oral, topical…). We use the 1% injectable form and give it orally at a dosage 0.05cc per bird and then repeat 2 weeks later. The unofficial withdrawal time is 21 days.

  • Fipronil (Frontline and many others) is a slow acting insecticide that is very effective against all kinds of external parasites. It’s used to prevent ticks and fleas on cats and dogs. It’s also not approved for chickens by the FDA. Although very little research on egg withdrawal period has been done, it seems that it stays a very long time in the chicken. There is not even an unofficial withdrawal time. We used it since we didn’t worry about the withdrawal period as we aren’t eating our chickens nor their eggs, but we aren’t recommending it anymore.

We are often asked about more natural ways to get rid of parasites such as putting herbs in the coop. Truthfully, there isn’t much research that has been done on the use of herbs as insecticides or insect repellents. However, sprinkling herbs such as lavender, marigold, and rosemary won’t harm your chickens and may discourage some of the parasites. But these herbs won’t kill these micro predators and treat an infestation.

If this article makes you itch then imagine how the chickens suffer from these pests, some of which can kill. Be on the lookout, check your chickens often, and treat as soon as you see a few parasites crawling around.



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