Internal Parasites in Chickens

Identifying internal parasites in chickens. Treating parasites in chickens.

Keeping healthy chickens isn't always straightforward.  You may know that nutrition is key and that pasture-raised chickens tend to be healthier than cooped-up chickens.  But what about the parasites and dangers that you can't always see?

👉Speaking of chickens, if you want to really spoil your chickens, you'll want to get your hands on our FREE Homemade Chicken Recipes Guide. It's a collection of 25 recipes for homemade feed, treats herbal blends and more for your flock! Grab yours here!

Internal parasites can be troublesome because you can't see them on your chickens.  They hide within the chicken, often out of our sight unless they become trouble. If you start to see signs of internal parasites in your chickens, then you've got a problem on your hands.

With that being said, I've raised hundreds of chickens and I have over 20 years of experience raising chickens.  As long as you take care of your chickens, you're probably not going to have trouble with internal parasites.

​With that being said, it does happen from time to time.  There are tell-tale signs of worms that you can look out for.  Thankfully, there are also treatments that you can use to help your chickens out if they have trouble with worms.

Types of Internal Parasites in Chickens

There are two types of internal parasites in chickens- worms and protozoans.

It's important to note that we aren't discussing chicken diseases (although some of these parasites can carry disease-causing organisms).  The parasites themselves cause problems in organs in the chicken.

Worms are larger and are often visible with the naked eye.  Protozoans are small, microscopic parasites that can only be seen with a microscope.

Of the two, you're more likely to have problems with protozoans rather than worms.  This is especially true when dealing with young chicks.

​Each parasite has different symptoms and treatments.  Keep reading to learn how to identify worms and illness due to protozoans.

What are the symptoms of worms in chickens?

Worms and protozoans both prefer to live in the digestive tract of chickens.  This leads to symptoms that are related to digestion.

Some common signs of internal parasites in chickens include:

-weight loss
-watery or bloody diarrhea
-fewer droppings
-undigested feed in the feces
-eggs or worms in the feces
-reduced appetite

Roundworms in Chickens

Roundworms are found in poultry all over the world.  They generally live in the digestive tract, but they can migrate to other organs and areas of the body. There are three types of roundworms that can affect chickens- large roundworms, small roundworms and cecal worms.

What causes roundworms in chickens?

Chickens can get roundworms from a number of sources.

Roundworms can be spread from bird to bird easily.  They can be spread from wild birds to your chickens as well.

The life cycle of the roundworm is pretty simple.

1. The females lay eggs in the digestive tract.  The eggs pass through the bird and are shed with feces.
2. Once the eggs are in the environment, they can live for years, waiting to be picked up by a feeding or drinking chicken.
3. The eggs hatch within the chicken, mature and lay eggs, repeating the cycle.

Large Roundworms

Large roundworms (Ascaridia galli), live in the intestines of chickens all around the world.  Large tapeworms are a common internal parasite.

These internal parasites don’t tend to cause too much trouble if the chicken is healthy and stress-free.  The issue occurs when the population of worms becomes too much for the chicken’s body to handle.

Roundworms can grow up to 4.5 inches in length.  They prefer to live in the small intestine.

If the population becomes too large, the adult worms will migrate to other organs like the crop, oviduct, cloaca, gizzard and the abdomen of the chicken.

If you crack open an egg and notice a tapeworm inside of it, that’s a sure sign that there are tapeworms living in the oviducts of your hen.

Roundworm eggs are quite hardy and can survive in the environment for years under the right conditions.  This is especially true in deep litter systems, which create an almost ideal environment for egg survival.

​One of the first signs of roundworms in chickens is the presence of undigested feed in the feces.

worms in chickens, parasites in chickens

Large roundworms can block the digest tract of chickens, making it hard for feed to be properly digested.  This results in feed slipping through the digestive tract without being properly broken down.

Since digestion is disrupted in chickens with tapeworms, you’ll see other signs related to digestive troubles.  A reduced appetite, decreased growth, diarrhea, weight loss and fewer droppings are all signs of a roundworm problem.

A for-sure sign of roundworms is the presence of worms or eggs found in the feces.

Large roundworms can be treated with various anti-parasitic, or anthelmintic, medications.

The only approved FDA approved treatment for deworming chickens in the U.S. is the drug Piperazine.

Various livestock dewormers can be used off-label to treat chickens for roundworms under a veterinarian’s supervision.

If you’re looking for a more natural approach, you can try citrus peel ethanolic extract, garlic or turmeric root extract.

​Remember, although roundworms can cause serious problems in large numbers, this isn’t something that you’ll probably have to deal with.  Healthy backyard chickens rarely have problems with roundworms.

Small Roundworms

Small roundworms, also called thread worms or hair worms, are caused by a number of Capillaria species.

Chickens with small roundworms act generally unhealthy and often have diarrhea.  You may notice weight loss, slow growth, decreased appetite or reduced egg production.  Left untreated, roundworm infections can lead to death.

​Small roundworms can look like small threads or hairs.  They don’t get much larger than 1 cm.

worms in chickens, parasites in chickens

The eggs can only be seen under a microscope.  Different species of roundworms prefer to live in different organs of the chicken.

Some species prefer the crop and esophagus, while others prefer the lower digestive tract.

Small roundworms live in the body of the chicken.

Females lay eggs in the digestive tract, where they are passed into the environment.  The eggs aren’t visible with the naked eye, so you won’t see them in feed, pasture or drinking water.  The eggs remain in the environment, waiting to be picked up by a feeding or drinking chicken.

Once they are consumed, the eggs hatch within the chicken and begin the life cycle again.

The worms feed on the organs of the chicken (crop, esophagus, small intestines or ceca).  They mature and the females lay eggs, beginning the cycle over again.

Some of the species of roundworms can infect earthworms, which act as an intermediate host until the earthworm is eaten and consumed by chickens.

Signs of a small roundworm infection include difficulty swallowing, head flicking, loss of appetite, weight loss and diarrhea.

If you suspect a small roundworm infection, you can take a fecal sample to your local veterinarian for testing.  Be sure to get dark colored droppings for a fecal sample and not droppings with a lot of white material.  Your veterinarian can test the feces for worms or eggs and recommend the proper treatment.

​There are many off-label treatment for small roundworms in chickens that use livestock or equine dewormers.  Be sure to talk to your local veterinarian to get the right recommendation for the type of small roundworms that your chicken has.

Cecal Worms

Cecal worms, Heterakis gallinarum, are worms that prefer to live in the ceca of chickens.

They are very common and can live on the ground or litter.  They are most common in overcrowded coops and runs.

The adults live in the ceca, where the females lay eggs.  The eggs are shed with the feces and enter the environment.  The eggs can live in soil or bedding for several weeks before being ingested by a chicken.

Once the eggs enter the chicken’s body, they hatch and move into the ceca.

Eggs can also be consumed by earthworms, a favorite food of chickens.  The cecal worms can then move into the chicken after the earthworm is eaten.

One of the problems with the cecal worm is that it carries the protozoan parasite Histomonas meleagridis.  This protozoan parasite causes blackhead disease.

Chickens with cecal worms will show signs of listlessness, poor appearance, dull feathers and depression.

​There are many off-label medications that can be used to treat chickens.


Tapeworms are flat worms that are easily identified by their segmented bodies.

worms in chickens, parasites in chickens

There are thousands of species of tapeworms that infect a number of animals.  The most common tapeworm species that affect chickens include Davainea proglottina, Raillietina echinobothrida, Raillietina tetragona and Raillietina cesticillus.

Tapeworms differ from roundworms in the fact that they anchor themselves to the walls of the small intestines.  Roundworms live freely in the intestinal tract and do not anchor themselves.  Tapeworms have mouthparts that are hooked and are used to anchor the worm to the lining of the intestines.

When tapeworms grow, they do so by adding segments to the body rather than simply increasing in size.

Tapeworms will consume nutrients from the bird, slowing growth and causing weight loss.

Tapeworms can also cause nutrient deficiencies and lower the immune response.  This can lead to secondary infections or diseases.

Tapeworms can damage the intestines, leading to peritonitis.  Secondary infections can spread to the head and sinus cavities, causing neurological problems such as wry neck.

Tapeworms have a more complicated life cycle than roundworms.

1. The mature tapeworms release body segments into the digestive tract.  These segments are shed with feces and enter the environment as eggs.
2. Snails, slugs, beetles, grasshoppers, ants, earthworms, flies and other arthropods and invertebrates consume the tapeworm eggs.  These insects and arthropods act as intermediate hosts for the tapeworms.  The eggs develop into larvae while in the intermediate host.
3. Chickens consume the infected insects and arthropods.  Once the infected host is consumed by the chicken, it is released into the chicken’s digestive tract.  They then latch onto the intestinal walls and absorb nutrients through the intestinal wall.
​4. Mature tapeworms then release segments into the digestive tract, starting the life cycle over again.

Signs of tapeworms include weight loss or slowed growth, despite a strong appetite.

Dull feathers and lethargy are common signs.  Neurological symptoms can also appear, including wry neck and paralysis.

White spots in the feces that look like grains of rice are segments of the tapeworm that have been shed.

​There are a few treatments that can be used off-label for treatment of tapeworms in poultry using livestock and equine wormers.


Protozoans are single-celled parasites that can infect chickens and other animals, including humans and pets.

​There are three types of protozoans that can infect chickens- coccidia, cryptosporidia and histomonads.


The most common protozoan infections are due to the coccidia.

There are nine types of coccidia, all belonging to the Eimeria genus.  Most species of coccidia live in the intestinal tract, but a few can infect the liver or kidneys.

Chickens become infected with coccidia by ingesting coccidia oocysts or eggs from the environment.  Most chickens are exposed to coccidia early on in low levels, which leads to a natural immunity in healthy chickens.

​However, young chickens or chickens that have a lowered immune system due to disease, stress or poor health can develop coccidiosis.

worms in chickens, parasites in chickens

Coccidia can damage the lining of the digestive tract, causing the body to leak proteins into the intestines.  The excess proteins disrupt the digestive process and can prevent nutrients from being absorbed.

Chickens can also become dehydrate and anemic.  Chickens that have coccidiosis will usually go off of feed and stop drinking, which causes further problems.

They become lethargic and prefer to be away from the other chickens in the flock.

They may hunch up and have ruffled feathers.  Chickens with coccidiosis will have runny poop that may not be the right color.  Bloody feces are also fairly common.  The comb and wattles of the chicken may be pale in color.

There are treatments for coccidiosis.  It’s best to attack a coccidosis outbreak from more than one angle, since the illness can affect the chicken in multiple ways.

​To kill the coccidia, use an anticoccidial medication containing amprolium or toltrazuril.

​Coccidia can lower the immune system and lead to secondary infections from bacteria.  To prevent secondary infections, use an antibiotic containing tylosin or amoxicillin.

Chickens with coccidiosis may not drink enough and should be monitored.  One of the causes of death from coccidia is due to dehydration, so keep the chicken hydrated.

It’s safe to assume that if one chicken has coccidiosis, then the environment is infected.  Clean out the coop and run, removing all feces and bedding.

​Don’t overcrowd birds in a coop.  Keep bedding dry and remove wet and soiled bedding.

Only treat birds for coccidia if they are showing symptoms.  Over-treating birds for coccidia has created drug-resistant strains.  If you have to treat your chickens for coccidiosis, it’s a good idea to have fecal tests done after treatment to make sure that the treatment was effective.


Cryptosporidiosis is the name of the disease that is caused by an infection of the protozoan parasite Cryptosporidium.  There are several species of Cryptosporidium that infect chickens.

They can live throughout the digestive tract and infect other organs of the bird, including the lungs, eyes, kidneys, cloaca and other organs.

Chickens can get cryptosporidiosis when they ingest the eggs of Cryptosporidium.  The eggs are shed into the environment where they can be ingested by chickens and other birds.

The eggs can survive in the environment for months at a time.  They survive well in cool, moist environments.  Because of this, they are often found in or near water sources.

Chickens with cryptosporidiosis will have an unthrifty appearance.  They may have pale combs and wattles and ruffled feathers.

Chickens may sneeze, have runny noses and eyes and cough.  You can sometimes hear rattling when the chicken breaths.  They can also have diarrhea and undigested food in their feces.

To treat chickens with cryptosporidiosis, isolate them in a warm, comfortable space with food and water.  Paramomycin can be given to kill the protozoans.

​To prevent cryptosporidiosis, keep the coop clean.  Elevate waterers to prevent birds from contaminating the water with feces.  Birds that are flying above the coop can also contaminate water with feces, so keep waterers under a roof if possible.


Histomonas meleagridis is a protozoan that is carried by the cecal worm.  It causes histomoniasis, or blackhead disease.

The protozoan rarely causes problems in chickens but it can have serious impacts in turkeys.  Turkeys raised in the same area as chickens are more likely to develop blackhead disease.

The most effective treatment for histomoniasis is to control cecal worms.

Young birds infected often die quickly before they can develop signs of the disease.  Older birds will become lethargic, go off of feed and appear poor.

​They may not hold their wings up or preen themselves, creating and unthrifty and sick appearance.  Birds that have been infected for some time will have yellow droppings as the disease progresses.  Even though the disease is commonly called blackhead, the head of the infected bird does not actually turn black.

Chicken Parasite Identification

One of the best ways to identify internal parasites is by looking at the feces of the chicken.  Worms and eggs can be seen in droppings.  However, you won't be able to see protozoans in the feces.  You'll need to collect fecal samples and have your veterinarian examine them under a microscope to identify them.

worms in chickens, parasites in chickens

What do worms look like in chicken poop?

Worms are easy to see if they find themselves being shed in the feces.  Roundworms and tapeworms are both white in color and should be easy to see against the dark droppings.

​Roundworms are long, skinny, and round.  Tapeworms are flat and ribbon-shaped.  Tapeworms are also segmented instead of smooth.  Tapeworm body segments are also visible in feces and look like grains of white rice.

How do you treat parasites in chickens?

The treatment for the parasite depends on the type of parasite.  Worms can be treated with antihelminthic, or deworming, medications.  Many treatments that your veterinarian may recommend are actually off-label treatments using livestock or equine wormers.  Talk to your vet to determine the best course of action for your chickens.

Protozoan infections can be treated with medications to kill the protozoan.  You'll also need to prevent secondary infections with an antibiotic.  Protozoans can hide out in the coop easily because we cannot see them.  Clean and sanitize the coop, feeders, and waterers.  Remove and replace all bedding.

​Find coop cleaners and sanitizers here

How often should you worm chickens?

Odds are that you won't have an issue with worms in your chickens.  Most chickens are exposed to them in small amounts over their lifetime and develop a natural immunity to parasites.

Worms and protozoans can develop an immunity to medications if they are used as a preventative.  You don't want to create drug-resistant parasites.  To avoid that, only worm your chickens if they are showing signs of illness from an internal parasite.

​Treating for parasites when they don't have a large parasite population can create drug-resistant parasites that are extremely difficult to get rid of.

How to Worm Chickens Naturally

If you want or need to worm your chickens, there are some treatments that you can use to do this naturally.  You can purchase natural remedies that will worm your chickens or you can use herbs and other treatments to worm them.


VetRX Poultry Remedy is something that you definitely need in your chicken first aid kit.

It's so useful to have.  It's a natural treatment and it's really good to have around if you need to worm a chicken.

Simply add a few drops to the drinking water to treat the entire flock.  If you only have one chicken that needs treatment, you can treat them individually also.

​Buy VetRX Poultry Remedy here

Verm-X Wormer Pellets

This is a really good option if you want to measure a scoop out and feed it.

It's all-natural and the guesswork has been done for you.  Simply scoop out the amount you need and feed it as you would feed.  Your chickens won't know that it's medicine and not feed!

​Buy Verm-X Natural Wormer Pellets here

Herbs to use for deworming

It seems like there is an herb to cure almost everything now!  I used to be skeptical of herbal treatments and thought that they were a fad that would pass.  Boy, was I wrong!

Herbs are becoming more and more popular as natural cures are being researched more.  It turns out that many herbal treatments really do work and there is scientific proof to back it up.

Here are the herbs that are most effective at getting rid of internal parasites in chickens:

-Black Cumin-  Black cumin may also go by the name of black seeds, black caraway, black onion seed, or kalonji.  Not only will it worm your chickens, but it will increase egg production, egg weight, and shell quality and decrease the concentration of cholesterol in the egg yolk.  It's also a proven antibacterial that reduces E. coli and an antiviral herb that can kill the virus that causes infectious bronchitis.

Buy black cumin here

-Blueberry-  Blueberries are full of antioxidants, and are often called a superfood for good reasons.  They aren't only something that can help deworm your chickens, but they can reduce stress.  They also have antibacterial properties.

Buy blueberry extracts, concentrates and powders here

-Chicory-  Chicory is probably best known for its use as a coffee substitute.  However, it is a really powerful food that can deworm your chickens.  It also has antibacterial properties, can improve gut function, and help protect your chicken's liver.  It's a really good source of vitamins K, A, and C, making it a great feed additive for your laying hens.

Buy chicory here

-Citrus Peels-  Your chickens more than likely won't eat citrus peels if you just peel an orange or grapefruit and try to feed it to them.  You can buy powdered citrus root extract that you can hide in their feed to use as a powerful dewormer. Citrus peel extract (600-1200 mg/kg) given for 14 days has been shown to significantly reduce roundworms (Ascaridia galli) in chickens.

Buy citrus peel here

-Fennel-  One of the worst types of worms that you may find yourself dealing with is coccidia.  These are more likely to strike your young, small, cute chicks that don't have the strong immune systems yet to fight them off.  Luckily, fennel has been shown to be a powerful tool when fighting coccidiosis in chickens.  It also has loads of other benefits, including antifungal, antimicrobial, and antiviral properties.

Buy fennel here

-Garlic-  Garlic is extremely useful if you keep chickens!  Adding 2.5 mg/bird of garlic to the diet of chickens can help to get rid of roundworms (Ascaridia galli). Garlic can also be used to help fight off coccidiosis.  If your chicken has ascites, you can use garlic to help treat it.  It's also an effective snake repellent, rodent repellent, antibacterial and insect repellent.  In fact, you can use it to control Northern fowl mites and red mites.

Buy garlic here

-Turmeric-  In 2015, a study tested the effects of using turmeric to treat roundworms (Ascaridia galli).  The turmeric reduced the length and width of the worms in the digestive tract of the chickens.  High concentrations of turmeric (600 mg/kg of body weight) helped to heal the chicken and restore the intestinal lining back to a healthy state. Turmeric can also be used to treat mycotoxins and ascites.  It also has antibacterial, antifungal, antiviral, and antiulcer effects.

​Buy turmeric here

Will apple cider vinegar kill worms in chickens?

Yes and no.

Depending on what you read, you may see where people recommend worming chickens with apple cider vinegar (ACV).

Apple cider vinegar itself probably isn't going to get rid of large worms like roundworms and tapeworms.  However, it has been proven to get rid of protozoan-type worms.

A study in 2018 compared the effects of ACV against coccidia in chickens.  They compared this to amprolium, a common medication used to treat coccidiosis.  The chickens that were given ACV showed no signs of coccidiosis while some of the chickens that were treated with amprolium did develop coccidiosis.

The easiest way to give your chickens apple cider vinegar is to put it in their drinking water.  Add one tablespoon of quality, organic apple cider vinegar to one gallon of drinking water.

Don't worry about your chickens not drinking the water once you put apple cider vinegar in it.  There are multiple studies that show chickens actually prefer the taste of water that has ACV in it.

Chickens tend to eat things that are good for them, the same is true for their drinking water.  ACV has been shown to increase mineral absorption in chickens, including calcium.  It also helps to keep bacteria and algae from growing in the waterers.

Make sure that you only use apple cider vinegar in waterers that are made of plastic as it can cause metal and galvanized waterers to rust.

​Buy apple cider vinegar here

Can you eat chicken eggs if they have worms?

It is completely safe to eat eggs from chickens that have worms.  I would crack eggs open before eating them to make sure that the inside of the egg is worm-free.

worms in chickens, parasites in chickens

There is a very, very small chance that worms can get into the oviducts of chickens.  The oviduct is where the egg develops.  When chickens have extremely large populations of roundworms, these worms will crowd the digestive tract so much that they start to migrate to other organs.  Sometimes, they make their way to the oviduct and there have been some reported cases of chicken eggs having worms in them.

​Again, this is extremely rare and not something that you are probably going to see in your chickens.  You'll likely see the symptoms of worms in your chickens before you'll notice worms in the eggs.

Can humans get parasites from chickens?

I'll also say that worms (like tapeworms, roundworms, and cecal worms) that your chickens get will not affect you, even if you were to accidentally ingest them.

Worms are species-specific. This means that they must be in a certain species of animal in order to survive.  Worms that affect a chicken will not affect humans, dogs, cats, other livestock, etc.  They cannot survive if they find themselves in a species that they aren't designed for.

You can read more about the general life cycle of worms here.

​None of the internal parasites listed on this page will affect humans.

Final Thoughts

Generally speaking, you won't have to deal with internal parasites in your chickens.  Keeping them healthy and keeping the coop, feeders, and waterers clean will prevent most worm problems.

The most common internal parasites that you could see are roundworms, cecal worms, tape worms, coccidia, cryptosporidium, and histomonads.

There are symptoms that you can look out for.  If you notice chickens that look like they don't feel well, aren't eating, have diarrhea, lose weight, stop producing eggs or anything else out of the ordinary, you may want to have a closer look at them.

You can also check the droppings to see if you can see worms.  If you don't see anything but you suspect worms, take the droppings to a veterinarian to have a fecal test done.  They can tell you what kind of worms your chicken has and the best method to treat it.

Traditional medications can be used to treat worms.  You can also use natural pre-made wormers or herbal treatments.  Apple cider vinegar is effective in treating coccidia, and makes a wonderful additive to drinking water.

​You won't get worms from your chickens, even if you come into contact with them.  They can cause problems for your chickens and need to be treated if they become an issue.  Don't over-treat your chickens for worms or parasites because over-treating them when they don't really need it will lead to parasites that are immune to medications.

​If you haven't yet, grab your FREE copy of the Homemade Chicken Recipes guide and get instant access to 25 recipes for making homemade feed, treats, herbal blends and more that your flock will love!

worms in chickens, parasites in chickens

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How do you treat parasites in your chickens?  Let me know below!

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