Coccidiosis in Chickens – Causes, Recommended Treatment and Prevention in 2024

Have you noticed bloody droppings coming from your chickens? The first disease that springs to mind is there is likely to be coccidiosis in chickens. What is coccidiosis in chickens, what causes it, how do we treat it and more importantly how do we prevent it?

coccidiosis in chickens
Coccidiosis in affected chickens can quickly result in death if not treated early enough (source:

Coccidiosis is a parasite which damages the internal gut wall of young chickens before they reach maturity. There are a number of species of coccidiosis. Their effects vary from harmless right through to life threatening.

Read on to find out all about coccidiosis in chickens.

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Coccidiosis develops quickly, with an incubation period of 4 to 8 days. Symptoms may develop gradually or appear suddenly. It is not uncommon for a chicken to seem fine one day and become very sick or even die the next.

Your chicken may be suffering from coccidiosis if you notice the following symptoms –

  • Slow growth, especially in young birds
  • Damage to intestinal lining
  • Change in droppings (diarrhoea, mucus, blood)
  • Weight loss
  • The bird may stop eating
  • Pallor and anaemia
  • Death can occur quickly as internal damage is done before you notice any symptoms.

Some birds can carry these organisms and may not show signs of illness. It can be a good idea to do regular fecal sampling via a home test kit and send it for analysis to your local vet clinic to determine if your flock is at risk of causing infection.

Coccidiosis affected faeces showing mucus and blood (Source: Poultry World)

Causes of Coccidiosis in Chickens

There are six species of Eimeria (coccidiosis) which are generally considered to be significant for chickens: E. tenella, E. brunetti, E. necatrix, E. maxima, E. mitis and E. acervulina.

For the purposes of treatment and prevention of coccidiosis it is unimportant to ascertain which species is causing disease in your birds and in many cases several species may be working together to cause disease. 

The life cycle of coccidiosis starts with what is known as an unsporulated oocyst. Basically it is like an egg containing an early stage of coccidiosis which is yet to develop. In this state the oocyst is unable to cause disease if eaten. The oocyst sprorulates (develops so that it becomes infective) in as little as 24 hours under optimum conditions (a humid environment at 25-30ºC or 77-86ºF).

The oocyst has a thick wall which protects it from heat, cold and even common disinfectants. This enables coccidiosis oocysts to survive for up to several years and makes it difficult to destroy them.

When the oocyst is eaten by the chicken, chemicals in the gut break down the oocyst wall and release the infective form of the coccidiosis called the sporocyst.

These sporocysts change into sporozoites which invade the cells of the gut wall and replicate. When the sporozoites have replicated in the cell, the cell bursts releasing another stage of coccidiosis called merizoites. These merizoites go on to invade and destroy more of the cells in the gut wall. Eventually the coccidiosis infection results in the production of more oocysts which are passed out with the faeces into the environment and can go on to infect other chickens.

In an ideal situation chickens exposed to low levels of coccidiosis will build up a natural immunity.

In general, immunity is not given from the hens to their chicks. Chicks will get exposed to coccidiosis in the first few weeks of life and will go on to develop immunity with or without clinical disease.

coccidiosis in chickens
A coccidiosis oocyst magnified (source: Bird Vet Melbourne)

How to Prevent Coccidiosis in Chickens

The best way to handle an outbreak of coccidiosis is to prevent one from occurring in the first place! While these measures won’t always prevent an outbreak, taking these steps can go a long way to ensuring the health of your flock.

  1. Properly clean coop and run area and disinfect with poultry specific disinfectant such as ‘Interkokask’ to remove and destroy the coccidiosis oocysts. This involves removing the old litter, using a detergent to remove dirt and grease so that the disinfectant can work.
  2. Control the humidity and ensure good ventilation.
  3. Keeping their bedding dry, this may involve topping up the bedding or using drying agents such as ‘Coop Refresher
  4. Always provide clean and fresh water.
  5. Try and keep feed off the ground to minimize oocyst contamination.
  6. Do not overcrowd your chickens – each chicken should have at least 4 square feet of space.
  7. Give your chickens immune boosting supplements.
  8. If introducing new flock members, its best to quarantine them for at least 3 weeks to monitor their health and prevent disease exposure to existing flock members.

For most backyard chicken owners, the above steps should be sufficient to prevent disease outbreaks. In larger scale holdings, medication can be used to control coccidiosis.

A vaccine is available commercially, however its administration can be complex and needs the correct environment to work, realistically this is not currently practical for backyard chicken keepers.

If you are concerned about coccidiosis then consult your veterinarian. Buy a Fecal Worm Egg Kit, whereby you collect some droppings from your birds vet laboratory, the droppings are tested for coccidiosis and worm eggs and you will receive your results usually within 48h hours.

There are many preventative measures you can take to reduce the risk of coccidiosis in your chickens

Treating Coccidiosis in Chickens

Luckily, coccidiosis is treatable if caught early enough in its advancement. It is important to treat every bird in the flock to contain the outbreak.

Treatment of coccidiosis generally involves four steps:

  1. Kill the coccidiosis in the birds to stop further gut damage, this usually involves giving an oral Anti-Coccidial Medication such as CORID (active ingredient is ‘amprolium’). Note: chickens eggs can still be eaten when using this product.
  2. Levels of coccidiosis can be detected if you send a fecal sample to your local vet using a Fecal Worm Egg Kit.
  3. Control the bacterial disruption to the gut, this is treated by antibiotic therapy.
  4. Provide your bird with a warm, dry environment and following any medication advice from your vet.
  5. Follow up with giving your medicated chickens Multivitamins and a Probiotic to restore gut flora.


Causes and treatment of Coccidiosis –

Prevention of Coccidiosis –

Wanting to learn about other health matters regarding your chickens? Water Belly is another common health condition that can affect your flock. Learn how to identify, treat and prevent this condition by reading our guide here.

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Are you looking for a shopping list of everything you need when caring for your precious flock? We have put together an easy reference of items for your convenience. 

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The team at My Chicken Guide are chicken enthusiasts! Our team has over 20 years experience in raising and caring for chickens. Our head writer is a qualified Environmental Scientist with a passion for sharing science based information on chicken care.

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