Coccidiosis: What Backyard Chicken Keepers Should Know

The diseases and parasites sections of chicken-keeping books have always intimidated me and with good reason: there's a lot that can go wrong with our pet chickens and very few reliable places to turn when it does. However, most things that can go wrong usually don't and when diseases do rear their ugly heads, they ordinarily extend the courtesy of taking turns, allowing us to research and address one at a time. Coccidiosis is one of the common diseases in chickens and one that every chicken keeper should know about before the first chick's feet hit the brooder floor. With a little common sense and good flock management practices, cocci can be controlled and easily treated when necessary.

WHAT IS COCCIDIOSIS?

Coccidiosis (aka: cocci) is a common intestinal disease caused by several species of parasites. The parasites rapidly multiply, damaging the intestinal lining, preventing chickens from absorbing nutrients from their food.

The microscopic cooties that cause cocci are everywhere. (of course that's a technical term) Chickens can be affected by cocci even with the best coop sanitation and flock management practices. The key to keeping chickens healthy is learning to control the spread of the disease, recognizing the symptoms when they occur, obtaining a definitive diagnosis and knowing how to treat an affected bird.
SYMPTOMS

The most common symptoms of cocci are:

• diarrhea and/or blood and/or mucous in droppings
• lethargy, listlessness
• pale skin color
• loss of appetite
• weight loss in older chickens
• failure of chicks to grow/thrive
• progression of symptoms can be gradual or rapidly result in death, particularly in chicks

Eimeria tenella oocysts from chicken feces. 

HOW IS IT SPREAD?

Microscopic eggs, called oocysts, are ingested, then multiply in the intestines and are expelled in droppings.  The eggs can be carried by wild birds, chickens from different flocks, on a person’s shoes, clothing or equipment. Cocci is commonly transmitted through dirty water or contaminated food. There are a number of species of Coccidia that affect chickens and immunity can be acquired by gradual exposure over time.

An example of how easily flocks can become infected:
Farmer Fred’s flock appears healthy and is, possessing immunity to the particular species of oocysts living in his yard. Fred finishes up his morning coop chores and walks over to farmer Betty’s chicken yard with his shovel to help her dig some fence posts. Oocysts traveled with him on the soles of his boots, his shovel and his clothes and were deposited in Betty's yard. The grass contaminated with the eggs was eaten by Betty’s grazing hens and they got sick with coccidiosis within a week of the visit. Fred brought home oocysts from Betty's yard with him to his hens and they began dying. Betty’s flock had not no immunity to the cocci species in Fred's flock and vice versa. 

PREVENTION

• Vaccinate day old chicks against coccidiosis. (many hatcheries offer this service at a nominal charge)
• Provide medicated starter feed to chicks that are not vaccinated for cocci. (the vaccine and the medication in chick starter feed taken together renders chicks unprotected)
• Keep brooders and coops clean and dry. (warm, wet conditions such as soiled, damp, brooder bedding, provide the ideal environment for eggs to multiply quickly).
• Provide the cleanest water possible. (very seriously consider employing poultry nipple waterers) 
• Don’t overcrowd living quarters (provide a minimum of: 4 square feet per adult bird inside coops, 10 square feet per bird in the run, and 6 square inches of brooder flooring for week old chicks)
• Ensure adequate coop ventilation to promote dry litter.
• Promote acquire immunity by introducing chicks gradually to a properly maintained chicken yard and existing flock by 4 weeks old.
• Practice good bio-security, including quarantining new flock members for a minimum of two weeks, restricting access to your chicken yard by fellow chicken-keepers, not sharing equipment with fellow chicken-keepers.
• Keep waterfowl separate from chickens (spilled water + warmth=ideal conditions for breeding cocci)
• Don't throw feed or treats on the ground where it can become contaminated.

DIAGNOSIS

The only way to properly diagnose cocci in living chickens is to have a fecal float test performed by a vet. Most veterinarians will gladly perform this test for a nominal fee, if any, even if they do not treat chickens.

The sooner cocci is identified, the sooner treatment can begin and the lower the risk of death. It is extremely helpful to have a droppings board in the coop in order to make a daily droppings assessment. Abnormal or bloody droppings should be tested.  

TREATMENT

When one chicken is diagnosed with cocci, the entire flock must be treated. The chickens that produced the droppings in the following photos were diagnosed with cocci. Following the advice of my vet, I treated my flock with 9.5cc of liquid amprolium (brand name Corid) per gallon of water for 4 days. The droppings were free of blood within 24 hours of the first dose, however, in 2 weeks, they were again medicated for 3 additional days. (The vet indicated that given the life cycle of Eimeria, no bugs would be present to kill less than 2 weeks after stopping treatment, hence the 2 week break in dosing.)
POST-TREATMENT
AFTER the treatment for cocci is completed, particularly when using amprolium, a vitamin supplement should be given  to replace the Vitamin B1 lost during treatment. A product such as Nutri-Drench will do the trick.

Questions regarding ‘egg withdrawal periods” always arise when drugs are given to laying hens. Discuss the matter with your vet and use your best judgment. (that's really helpful, isn't it?)

VIEWER ADVISORY: The following video is an excellent presentation on the subject of cocci, however, it is extremely graphic and may be difficult to watch. There are overcrowding conditions and dead or dying birds shown in both clinical and brooder settings.

Further reading and sources:

http://cal.vet.upenn.edu/projects/parasit06/website/lab2.htm

http://www.accessdata.fda.gov/scripts/AnimalDrugsAtFDA/index.cfm?gb=2

https://animalhealth.pfizer.com/sites/pahweb/US/EN/Conditions/Pages/Coccidiosis.aspx

http://www.millerhatcheries.com/Information/Diseases/coccidiosis.htm
http://www.thepoultrysite.com/publications/2/Coccidiosis%20Management/46/drugs 

The Chicken Health Handbook, Damerow, Gail. Storey Publishing, 1994.

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This post is shared with: Down Home @Tilly's Nest, Homestead Barn Hop @Homestead Revival,  Weekly Top Shot @The View from Right Here Wicked Good @The Wilderness Wife