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Western Small Flocks Collaborative

Coccidiosis

Learn about what coccidiosis is, prevention methods, and how to minimize your birds’ risk of developing it.

Coccidiosis Factsheet
Silhouette icon of a Coccidiosis virus shape

Quick Facts

Silhouette icon of a Coccidiosis virus shape Caused by Eimeria protozoan parasites
Silhouette icon of a Infectious Laryngotracheitis virus infected chicken Spreads quickly and can cause severe illness or death
Silhouette icon of a light brown turkey Can infect turkeys, ducks, geese, and gamebirds, each species has its own type of Coccidiosis
Silhouette icon of a dark brown human figure Does not spread to or infect humans
Silhouette of light brown sun with a dark brown center Most common during warm, wet months

What is Coccidiosis?

Coccidiosis is caused by Eimeria, tiny protozoan parasites that damage the intestinal lining. Disease can result in poor nutrient absorption, weight loss, slow growth, poor health, and even death. Young birds are more likely to get sick. Birds become infected when they ingest oocysts (parasite eggs) in contaminated feed, water, soil, or droppings. Coccidiosis spreads quickly and can infect the whole flock if not treated.

Silhouette icon of a brown caution symbol with an exclamation point in the center One infected bird can shed millions of oocysts each day.
Chicken experiencing Coccidiosis with depression, ruffled feathers and pale skin
When coccidiosis is advanced, chickens often look depressed, with ruffled feathers and pale skin.

Signs of Coccidiosis

One sick bird may be the first sign of a bigger problem. The parasites spread quickly. Its life cycle takes 4 to 7 days and can infect your whole flock before many birds show symptoms.

What to watch for in your flock:

  • Diarrhea, sometimes watery, foamy, or with blood
  • Birds eating less and losing weight
  • Slow growth or “failure to thrive” in young chicks
  • Ruffled feathers and tired, droopy appearance
  • Dehydration (sunken eyes, dry look around the beak)
  • In severe cases, sudden death, especially in young birds

Course of Coccidiosis:

  • Birds pick up parasite eggs (oocysts) from contaminated litter, droppings, or soil.
  • The parasites invade the gut lining and multiply, causing damage to the intestines.
  • As damage builds, birds show signs like diarrhea, dehydration, poor growth, and weakness.
  • Mild cases may recover over time as the gut heals.
  • Severe infections, especially in young chicks, can cause sudden death.
Chicken diagram with signs of Coccidiosis
Common signs of coccidiosis include diarrhea (sometimes bloody), pale combs, ruffled feathers, loss of appetite, poor growth, weight loss, and birds appearing weak or huddled.

How does Coccidiosis Spread?

Contact with contaminated droppings

  • Birds become infected when they eat or drink anything contaminated with droppings that contain coccidia oocysts (parasite eggs).

Build-up in the environment

  • Oocysts survive in litter, soil, feed, and water.
  • Wet, dirty, or crowded conditions let oocysts multiply quickly, raising the risk for the whole flock.
  • Wild birds can shed oocysts, especially to outdoor flocks.

Bird-to-bird exposure

  • Healthy birds pick up oocysts shed by sick or carrier flockmates.
  • Young chicks are most at risk because they have less immunity.
Chicken diagram for how Coccidiosis spreading by ingestion of Oocysts parasite eggs, digestion, droppings, and back again by a bird ingesting Oocysts eggs
Birds eat parasite eggs, coccidia multiply in the gut, and new eggs are shed in droppings, repeating the cycle.

How Do You Treat Coccidiosis?

There is no home remedy for coccidiosis. Work with your veterinarian to have your birds tested and treated. In some cases, medicated feed (with approved anticoccidial agents) can be used under veterinary guidance, but always read the label and follow directions. Support sick birds by keeping housing clean and dry, isolating affected birds if possible, and ensuring they have plenty of fresh water to prevent dehydration.

How Do You Prevent Coccidiosis?

Keep the Coop Clean and Dry

  • Coccidia thrive in wet, dirty litter.
  • Change bedding often, especially if it gets wet from spills or droppings.

Use Clean Feeders and Waterers

  • Don’t feed birds directly on the ground.
  • Keep food and water containers clean to prevent contamination with droppings.

Give the Flock Space

  • Overcrowding stresses birds and allows disease to spread.

Reduce Stress

  • Stress weakens immunity and make birds more susceptible to disease.
  • Reduce drafts, sudden diet changes, or crowding.

Handle Healthy Birds First

  • Care for birds in this order: young → adults → sick, to avoid spreading germs.
  • Wash or sanitize hands and equipment between different bird groups.

What if Coccidiosis is Found in Your Flock?

Work with a Veterinarian

  • Diagnosis is based on signs, a fecal test for oocysts, or a necropsy.
  • Fecal tests may not always detect coccidiosis since birds don’t constantly shed parasite eggs.
  • Necropsy is often the best test because a vet can see damage in the intestines, and if needed, take a scraping for microscopic confirmation.
  • Contact your veterinarian for guidance on testing and interpretation.

Treat with Medication

  • Your veterinarian can recommend the right medication.

Don’t Spread Disease

  • To stop the spread, don’t introduce new birds or sell birds until the outbreak is over.
  • Keep different age groups separate; older birds can pass the parasite on to younger ones.

Plan for Long-Term Management

  • Your veterinarian can help you create a plan to keep your flock healthy and prevent future outbreaks.