Loading... Please wait...

Sign Up for our Newsletter

Our Newsletter

Coccidiosis in chickens

Have you wondered what causes coccidiosis in chickens? The answer is coccidia.

Coccidia are microscopic parasites that infect the digestive tract of all chickens. Yes, that’s right, allchickens. And a small number of familiar coccidia are fine in a healthy, adultchicken. 

What causes coccidiosis in chickens is exposure to unfamiliar coccidia, really high levels of coccidia or exposure in chickens that are already unwell. And when coccidiosis is a problem, it is a PROBLEM. It spreads rapidly through a flock and causes death within a couple days. 

That’s why knowing how to recognise the signs of coccidiosis in chickens, and how to prevent it, is essential for the backyard chicken keeper. 


If you need to buy coccidiosis treatment for chickens, click here.


Signs of coccidiosis in chickens

All chickens carry some coccidia in their intestine. These coccidia should not cause any symptoms or ill-health. However, signs of coccidiosis that needs treatment include:

  • Bloody or watery diarrhea

  • Lethargy

  • Lack of appetite

  • Pale combs and wattles

  • Droopy posture and wings

  • Ruffled or puffed up feathers

  • Droopy, dull or glazed eyes

  • Poor growth in chicks

  • Death

Coccidiosis in chickens usually affects:

  • Young birds and chicks that have not yet developed sufficient immunity to the parasite

  • Chickens that are otherwise unwell, for example chickens suffering from malnutrition, other diseases, high parasite loads or stress

Coccidiosis is unlikely to affect normal, healthy, adult chickens unless a new strain of the parasite, to which the birds don’t have immunity, is introduced to the chicken coop. But this happens more often than you’d think.

Coccidia vary greatly between sites, so you probably have entirely different strains in your coop to your neighbour. This means it is easy to introduce new coccidia – even dirty shoes from someone else’s coop are enough, let alone new birds! 


What causes coccidiosis in chickens?

Like most intestinal parasites, coccidiosis is spread by eggs (oocysts), which are laid in the guts of the infected host and passed out through their faeces. The life cycle begins again when these eggs are consumed and hatch in the new host’s intestine. The parasite burrows into the gut lining and impairs digestive function as it multiplies and produces more oocysts. 

Oocysts are spread by chicken faeces and wild bird faeces. They can survive up to a year in warm, wet conditions, so maintaining a clean, dry coop can greatly reduce the number of oocysts your birds are exposed to.

Coccidiosis outbreaks can be associated with:

  • Warm, wet conditions

  • An unsanitary and/or overcrowded coop

  • Other causes of stress such as illness, high parasite loads, malnutrition or environmental changes

Because “new” coccidia are the main cause of coccidiosis in otherwise healthy chickens, it is good to have an idea of some of the common ways these parasites may be introduced to your chicken coop. New coccidia can come from:

  • Wild birds in the coop.

  • Introducing new birds to your flock – this is the most common cause and can occur even when the birds appear perfectly healthy. Because remember, the deadly coccidia is their “normal”.

  • Travelling with your birds and bringing them home again, for example attending a chicken show.

  • A visiting chicken keeper with oocysts on their shoes, clothing or even vehicle tyres.

  • Using equipment that comes from another chicken keeper, such as a coop, feeder or even egg cartons, without cleaning and disinfecting it.

So practicing good chicken coop biosecurity is key!


How to prevent coccidiosis in chickens

There are two elements to preventing coccidiosis.

1. Treat young chickens until they can develop immunity to coccidia.

2. Good coop management, including biosecurity.


Young chicks must be treated to prevent coccidiosis. While some chicken keepers, in particular organic chicken keepers, may choose not to treat their chicks for coccidiosis, doing so is good practice. There are two options:


Many commercially purchased chicks and chickens will be vaccinated for coccidiosis. This vaccination is effective against most strains of the parasite. Vaccinated chicks should never be fed a medicated feed as this will nullify the protective effects of both treatments.

Medicated feed

Rather than vaccinate, many backyard chicken keepers raise their chicks on a medicated chick starter. This feed contains a coccidiostat or anticoccidiosis medication. It is not strong enough to completely protect the chicks from the disease, but it provides enough protection to help them build the immunity that adult chickens have. Medicated feed should be fed only to chicks and should be used for up to 8 weeks. Eggs from chickens that have eaten a medicated feed should not be consumed.


Good coop management can also help prevent coccidiosis in chickens:


Below zero temperatures, direct exposure to UV radiation and hot, dry conditions will kill oocysts. 


How to treat coccidiosis in chickens

Coccidiosis spreads quickly, and survival often depends on rapid treatment. 

While you should always isolate sick birds immediately to prevent the spread of disease, if one bird is sick chances are high that the whole group soon will be. 

Treatment for coccodiosis is with sulfa drugs or Amprolium. We recommend Amprolium, because sulfa drugs can cause toxic overdose. Amprolium is available over-the-counter, and is an effective and quick coccidiosis treatment for chickens. We offer express shipping, because we know how important rapid treatment is.