Poultry Parasites

Scroll down to view info on the types of worms that chickens & other poultry can be infected with.

Caecal worms (Heterakis sp)

Heterakis (caecal worms) are  common small worms found in the caeca of poultry.

These worms thrive in dirty conditions and overcrowded coops & runs. 

While the worm itself rarely causes problems in chickens it is associated with another disease called blackhead disease (histomoniasis) which can affect turkeys, chickens & quail.

The caecal worm is an intermediate host for the protazoa that causes blackhead, so if a bird ingests one of these worm eggs it may also contain the protozoa, Once inside the turkey the protozoa can then enter the gut walls by using damage caused by the caecal worm, causing ulcers, peritonitis & can spread to the liver. 

Turkeys are especially susceptible to blackhead, with a mortality at nearly 100% for infected turkeys, which is 1 reason many keepers do not house turkeys and chickens together. Symptoms of blackhead disease appear in 7-12 days after infection, with sulfer yellow loose droppings & a blue/ black face discolouration.

Caecal worm eggs have been reported to survive up to 2 years in the environment in favourable conditions, so clean housing & regular testing is a good idea to help stop any infection taking hold, especially if you also keep turkeys.

Hairworms & Threadworms (Capillaria sp)

Capillaria are found in the osophagus, crop and small intestine of the bird. Some types have the earthworm as an intermediate host, meaning if your chicken eats an infected earthworm whilst foraging it can then become infected with these parasites. The symptoms of a capillaria infection are unthriftyness, slow growth rates, weight loss, reduced egg production & diarrhoea. 

Roundworms (Ascaridia sp)

Ascaridia is a common large ascarid of poultry that is white and round and measures approx. 5-10 cm in length. This worm is more dangerous in youngstock than in older birds. In youngsters it can cause blockages and inflamation of the small intestine (enteritis). Older birds tend to have milder symptoms. General symptoms of a roundworm infestation include paleness of the comb and face skin, a ruffled appearance, unthriftyness & depression. In deep litter systems & dirty housing the roundworms can remain infectious for years in the environment. Ascarid eggs have a thick tough outer wall which allows them to survive in many weather conditions. 

Gapeworm (Syngamus sp)

Gapeworm are different from other worms of poultry in that they dont live in the intestines but travel to the lungs and then trachea where they live as adults, causing blockage of the trachea and the characteristic rasping gurgling noise together with the stretching of the neck and opening of the beak to try and gain more air. This is very common among pheasants but can also affect chickens, turkeys and guinea fowl. Heavy infestation can lead to death by suffocation. Young birds are particularly susceptible, but it can also occur in birds of any age.

The lifecycle of a gapeworm starts by the bird eating a gapeworm egg that has either been coughed up or pood out by another bird, or via an intermediate host such as an earthworm which may be infected. Once inside the bird the eggs hatch and burrow through the intestine walls, moving into the lungs and bronchi where they go through what is called a larvel moult, then moving up to the trachea as adults. Once there the males and females attach to each other creating a "Y" shape and breed. They are blood red in colour and 1-2 cm long. As they breed the eggs they lay are coughed up, either straight out onto the ground or else the bird swallows them and they get passed out in the poo, thereby allowing the cycle to start again in another bird.

Gapeworm symptoms can often get confused with respiratory illness as there can be similarities. If your bird is stretching its neck and opening its mouth rasping often, its worth doing a worm count as this will rule out the gapeworm as a cause and allow you to focus on other possible respiratory issues that may require antibiotics from a vet. For a positive gapeworm result in a worm count, treatment is Flubenvet wormer, along with good hygiene to prevent reinfection, such as using a sanitising disinfectant powder on the ground of any runs, and by clearing droppings as much as possible and ensuring droppings stay out of food and water sources.

Tapeworm (Various species incl. Davainea proglottina & Raillietina cesticullus

A number of tapeworm species can affect poultry, but rarely cause issues. Tapeworms steal food & essential nutrients from the bird as it feeds, & can in some cases cause nutrient deficiency & stunted growth. One species: Davainea Proglottina can cause intestinal damage in high numbers & possibly be linked with peritonitis & wry neck. 

Tapeworms have an indirect lifecycle, they have intermediate hosts that are then injested by your birds, such as snails, slugs and earthworms. 

Tapeworm are not reliably detected in worm counts due to the way they shed their eggs. By detaching a portion of themselves containing many eggs a poultry faecal sample may contain many or no tapeworm depending whether the egg section was shed in that moment.

Treatment for tapeworm can also be tricky as the only licensed poultry wormer (Flubenvet) is not considered particularly effective against these worms & does not list any tapeworm species in its targeted species list. A vet can prescribe off license products for use in tapeworm treatment if needed, which may include Panacur or Drontal.

Coccidia (Eimeria sp)

Coccidia are not worms but are parasitic protozoa which can cause the disease coccidiosis. They colonise the lining of the gut inside the bird and cause damage there. Infected and recovered birds shed the oocysts in their droppings. When these oocysts enter the environment they do something called  sporulation which causes them to become very resistant to disinfectants and drying agents. They can then go on to survive in the environment for a long time depending on the weather conditions and how dirty it is. 

The number of coccidia detected in a worm count may seem alarming as there can be a lot there, but poultry are capable of carrying a number of these without any harmful effects, so the numbers have to be considered differently to our regular worm cut off points for treatment.

Treatment for coccidiosis/and or coccidia oocysts present following a count is by using an anticoccidial agent which is added to the water. Some producers of poultry choose to feed their young chicks on a feed containing coccidiostats which stops the development of the infection, but others prefer to feed a drug free feed product.

Some poultry you buy both as day old chicks or as POL hens may have been vaccinated against coccidiosis. 

Coccidiosis is generally found among young birds especially chicks, and is often associated with dirty brooder conditions such as damp bedding or chicks pooing into their food and drink source. Good hygiene is key to prevention, and checking for coccidia oocysts via a worm count can give a useful insight into whats going on inside your youngsters.

Symptoms to look out for include listlessness, pale combs and wattles, huddled appearance, lack of appetite and blood or mucus in the droppings which are often loose.

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