Coccidiosis in Chickens

Keeping your backyard chickens healthy takes more than just providing them with food and shelter. While these are obviously both critical, you also need to maintain your chickens’ health and well being.

Like any other living thing, chickens can get sick and suffer from diseases. As the owner of backyard chickens, you need to be aware of this. Coccidiosis in chickens is one of the most common diseases that could impact your backyard flock. It is the foremost killer of brooder chicks.

medicated feed

What is Coccidiosis? What causes it?

  • Coccidiosis in chickens is caused by a parasite. Seven species of parasites can cause chicken coccidiosis, and these are present in chicken feces.
  • Chickens ingest the parasitic eggs from contaminated chicken droppings when eating, scratching at the ground, and drinking. (The parasitic eggs may remain dormant in soil for up to a year). The eggs pass into the chicken’s intestines, where the invasive parasites attach to the cells of the intestinal wall and replicate. New eggs are then eliminated in chicken feces and the cycle continues. This cycle takes just 4-6 days and relies on optimal temperature and humidity for the parasitic egg to become infectious.
  • A major problem in poultry farms (especially under factory farming conditions), coccidiosis damages the intestines of the bird. This prevents the chicken from being able to absorb essential nutrients which are vital to survival.
  • All chickens carry the Coccidia organism, but not all will become infected with the disease. The parasitic eggs may also be spread on equipment, clothing, and shoes.
  • Chickens are most susceptible to becoming sick from hatching to 6 months of age, as their natural immunity has not had time to develop.
  • Birds that survive infection will ultimately develop a resistance to it.

Signs and Symptoms

Some chickens will display few, if any, symptoms of coccidiosis, and may even recover quickly. Many infected birds will, however, become unwell and some will die.

Signs and symptoms of infection develop quickly after incubation over 4 to 8 days. Chicks can die in a matter of as little as a day.

Symptoms may include:

  • Mild to severe appetite loss
  • Weight loss
  • Failure to thrive
  • Listlessness
  • Weakness
  • Diminished egg-laying
  • Ruffled feathers
  • Diarrhea (may contain blood or mucous)
  • Dehydration
  • Death

If you suspect a chicken has coccidiosis, have your vet test a sample of their droppings as soon as possible.

Treating Chickens that are Infected

Anti-coccidial drugs are a form of chemotherapy used specifically for treating coccidiosis in chickens. These drugs are given in low doses as a prophylactic (preventative) in commercial chicken flocks.

If an infection is identified early enough, successful treatment is possible. Every bird in the flock must be treated even if only one is unwell.

chicken diseases

The drug Amprolium compromises the ability of the parasite to invade and multiply, and it is usually added to your flock’s water supply, otherwise, it can be directly given by mouth.

Stopping the spread of Coccidiosis to other Chickens

Eradication is not possible, so methods for control need to be applied. By allowing your chickens to build a natural immunity as well as preventing exposure, you stand your best chance of preventing issues in your own flock.

  • Hygiene is of paramount importance. Keep the clothing, shoes, and tools you use with your chickens exclusively for that purpose. Don’t risk exposing your chickens to other flocks, and vice versa.
  • When introducing new hens or a rooster to your flock, quarantine them at least 12 meters from your flock for no fewer than 3 weeks. Monitor the health of your new chickens during this time.
  • Provide plenty of space for your flock. Each bird needs at least 1.3 square meters of space inside the coop, 2.5 square meters in a run, and plenty of flooring in a brooder for baby chicks.
  • Provide clean, fresh water daily. Ideally, provide water for drinking via nipple waterers rather than open areas chicks can get into.
  • Keep the coop, roosts, nesting boxes and feeding areas clean and dry. Food thrown to the ground for pecking at can become contaminated. Remove soiled or damp bedding promptly.
  • Use medicated starter feed for unvaccinated chicks – but ONLY if your chicks are not vaccinated.
  • Vaccination is available to prevent infection in your chickens. It is given on the first day after hatching, is highly recommended, and is safe, even for chicks intended for the dinner table.
  • Provide probiotic supplements in your chicks’ drinking water to boost gut health.

Prevention is always better than cure.

Can Humans Catch Coccidiosis?


There are many types of coccidiosis and most are specific to a particular species. As such, chickens can’t be passed to humans (there are, however, some other chicken diseases that can be). Humans can spread chicken it via clothing, boots, shoes, and equipment – so it’s important to be aware of this.

Being aware of Coccidia organismpresent in chickens and taking steps to prevent it is the key to a happy healthy flock of backyard chickens who will thrive and lay plenty of eggs.