What is coccidiosis? Coccidiosis is one of the most common chicken ailments to affect young chicks. Coccidiosis is a protozoal disease that destroys the intestinal lining, causing malnutrition and sometimes unrepairable damage to the instestines. Since coccidiosis is so common, it is one of the biggest health concerns when raising young chicks. Learn how to diagnose coccidiosis in chicks so that you can be prepared to recognize even the earliest signs of cocci in your brood. Knowing how coccidiosis works and how to diagnose and treat it will help you raise a healthy homestead brood!

This post may contain affiliate links. See our Disclosure for more information.

What is Coccidiosis?

Coccidiosis, also known as cocci, is a disease caused by an intestinal protozoa called coccidia. There are 9 different species of coccidia protozoa known to affect chickens. Each species of coccidia infect a different part of the intestine and chickens can be infected by several different coccidia protozoa at the same time.

Coccidia protozoa are found nearly everywhere there are chickens present. Even healthy chickens probably have a small population of coccidia living in their gut. However, coccidiosis is a disease that chickens can build up natural immunity to. Even though coccidia may be present in the gut, the chicken’s immune system is strong enough to prevent the coccidia from becoming actively infective.

Immunity to coccidia protozoa must be aquired gradually. The immune system builds immunity to coccidia as young chicks mature and grow in an outdoor setting where they are exposed to small amounts of coccidia at a time. However, chicks can have immunity to one species of coccidia but not immunity to a different species of coccidia. It depends on what coccidia they were exposed to when building immunity.

Since coccidia immunnity must be built gradually, coccidiosis commonly affects young and growing chicks rather than adult chickens. Coccidiosis is most common in chicks between 3-6 weeks of age. By the time a chicken matures, it have developed enough immunity to not be affected by coccidia.

However, adult chickens can become infected with coccidiosis when their immune system is surpressed. A surpressed immune system will not be able to ward off the proliferation of the coccidia protozao, leading to an infection of coccidiosis. Immune system supression can occur when a chicken becomes ill with another disease, has external or internal parasites, or is affected by environmental stress or management stress.

Is Coccidiosis Contagious?

Coccidiosis is contagious, however, it must be spread through the consumption of the coccidia protozoa. Coccidia come in many different species and nearly all livestock animals can get a form of coccidiosis. However, coccidia is highly species specific amongst animals and even amongst different species of birds. For exmaple, the species of coccidia that affect chickens will not be harmful to dogs or horses.

Chickens who are immune to one species of coccidia can spread that coccidia to other chickens who have not been exposed to that coccidia before. Introducing chickens from two different flocks, or two different age groups, can cause that situation to occur.

Of the 9 species of coccidia that affect chickens, not all of them cause serious infections. Certain species of coccidia are more destructive than others. However, if a chicken is infected by severeal different species of coccidia it can be fatal as the protozoa destroy enough of the intestine to become dangerous.

Coccidiosis infections are generally classified into three categories.

Levels of Coccidiosis Infection

• Acute Coccidiosis: Acute cocci is the severest level of coccidiosis. It causes bloody diarrhea as the intestines are slowly torn apart by the protozoa. It is most common when a chicken’s environment is unsanitary or if the chicken has built up no immunity to coccidia.
• Chronic Coccidiosis: Chronic cocci is a mild level of coccidiosis. A chicken with chronic cocci will show no readily identifiable symptoms other than it may fail to thrive and produce well. Chickens foraging in areas with high concentrations of cocci oocysts (protozoal eggs) are more likely to contract chronic cocci but show no symptoms until under stress.
• Coccidiosis: Coccidiosis is the general condition of cocci that produces no detectable signs of infection. It occurs in birds who have developed immunity or who have been exposure to a species of cocci that doesn’t cause disease.

How do chicks get coccidiosis?

Chicks or chickens become infected with coccidiosis when they consume the protozoa from their environment. However, coccidia protozoa can only survive in an environment when chickens are constanly consuming and spreading the protozoal eggs, called oocysts. Coccidia have a direct lifecyle that is dependent on chickens. The direct lifecyle of coccidia also happens very rapidly, with infections occuring within a week or less of exposure.

The direct lifecyle of the coccidia protozoa works like this:

Coccidia Direct Lifecycle

• Cocci is present in the environment when an infected chicken poops out cocci egg cysts (called oocysts) in its droppings. Oocysts are impossible to see with the naked eye.
• Given the right environment, oocysts become infective when they sporulate. Occysts sporulate the most rapidly in an environment that is moist and around 70-90°F (think chick brooder).
• The sporulated oocysts can be spread as chickens interact with their environment, through contaminated food, water, litter, or equipment, and by being blown through the air.
• When a chicken consumes the oocysts from their environment (contaminated soil, food, water, litter, etc…) they become infected with cocci.
• Once ingested, the oocysts are broken down in a chicken’s gizzard, releasing zoites.
• Zoites then move through the digestive system and attach themselves to the intestinal wall, where they asexually reproduce to create more oocysts. The zoites feed upon the intestinal wall, causing intestinal damage that can be fatal.
• As the zoites reproduce oocysts, the oocysts are then carried back into the environment when a chicekn poops them out. Then the lifecyle can begin all over again if the occysts are able to sporulate in their environment.

Coccidiosis is a self-limiting disease. If the oocysts are unable to sporulate or a chicken no longer poops out occcysts, then the disease cannot spread. However, chickens who are infected by cocci or who are recovering from a cocci infection can shed the occysts into their environment. The oocysts can remain the environment for many months before they become activated by the correct sporulation conditions. Freezing weather or extremely hot temperatures (above 130°F) will kill off coccidia oocysts.

How do chicks build immunity to cocci?

Chicks can build immunity to coccidiosis when they are exposed to the coccidia protozoa in small amounts. The cocci oocysts can remain dormant in an environment that is not ideal for them to sporulate in. In this way, occysts are present in just about any outdoor environment. By exposing your chicks to the outdoors in short, gradual periods of time, you are introducing them to coccidia. Chicks raised by a mother hen are exposed to cocci through their environment and through their mother’s droppings.

When the chicks become exposed to small amounts of cocci, they are able to build up immunity to the protozoa. The protozoa are not numerous enough to cause an infection while the body builds fights them and builds immunity. Coccidiosis becomes dangerous when chicks are exposed to large quanities of cocci and are unable to build up immunity fast enough. Coccidiosis is rarely a concern in chicks under 3 weeks of age because the coccidia protozoa need enough time to accumulate to infective levels in the brooder.

How susceptable a chick (or chicken) is to getting coccidiosis is dependent on a few factors:

Susceptablity Factors

• Age– younger chickens haven’t had time to build up immunity to coccidia
• Status of Immunity– chicks can build immunity to one species of coccidia but be susceptable to species that they have not been exposed to
• Inherited Resistance– mother hens can pass down resistance to cocci to their chicks
• Nutritional Balance– a nutritionally balanced diet helps a chicken build and maintain a strong immune system
• Other Disease– if a chicken is infected by other diseases or parasites, it may have a surpressed immune system that is unable to fight coccidia
• Concentration of Oocysts– exposure to high concentrations of infective oocysts can be dangerous even for chicken who have built immunity to coccidia
• Cocci Strain– there are 9 different species of cocci, but those 9 species can even be present in different strains in certain environments

The more susceptable a chick or chicken is to cocci, the more likely it will show symptoms of a cocci infection.

General Symptoms of Coccidiosis

Coccidiosis is a disease that damages the intestines. When the intestines get damaged, a chicken will have a hard time digesting food or absorbing the nutrition from its food. Damaged intestines also make way for other intestinal disease to occur.

Here are some general symptoms that could indicate a chick or chicken is suffering from coccidiosis:

• decreased food & water consumption
• off-colored droppings
• bloody droppings
• dehydration
• hunched and inactive
• ruffled feathers

In growing chickens, those symptoms may also be accompanied by slowed growth rate, watery diarrhea, and potentially numerous deaths. Even though mature chickens are rarely affected by coccidiosis, some symptoms that may indicate a cocci infection include a decrease or sudden stop in egg production, pale skin, and weight loss. Pale skin in yellow-skinned chicken breeds can be an indication of cocci because the intestines are damaged and the body cannot absorbed the pigmentation from food in order to color the skin.

Coccidiosis can come on rapidly or show up gradually. Usually the first signs of a severe cocci infection are the presence of bloody stools. If allowed to progress, the cocci will destroy enough of the intestinal lining to cause hemorrhaging and death. If caught soon enough, the cocci may not have enough time to cause severe damage to the intestines. Minor intestinal damage may be repaired by the body, other times the intestinal damage is perminant and may affect the chicken for the rest of its life.

A chick, or chicken, who recovers from cocci may not be as productive or as strong due to intestinal damage. The chicken will be more susceptable to other ailments and may always struggle with keeping on weight and getting proper nutrition.

Bloody Droppings or Shed Intestine?

So you see red in your chicken’s droppings and you panic… its coccidiosis! Help! But…. not all red droppings mean coccidiosis. Intestinal lining is occassionally shed as a natural part of maintainng a healthy intestinal wall. The body expels the shed intestional lining in a chicken’s poop, which can often be mistaken for bloody stools.

Generally, if the red dropping is an isolated case and does not occur on a regular basis, you can assume that your chicken is not infected by coccidiosis. Keep an eye out for other cocci symptoms or for repeated bloody stools that would indicate a cocci infection.

Species of Coccidiosis

Identifying what species of cocci is affecting your chickens can be done by evaluating symptoms or getting a fecal test done. Having a fecal exam done may require some precious time when you’re dealing with a severe cocci outbreak, but it is also the most accurate way to know what cocci species you are dealing with in your brood or flock. Several fecal tests may need to be done is several cocci species are involved in the infection. Postmortem findings may also reveal if a chicken died due to cocci and what cocci species was the culprit.

Here are the 9 species of coccidia that infect chickens:

Coccidia Species

1. E. acervulina (chicks 2-4 weeks of age)- most common, slow growth, long infection time, watery & white diarrhea, low to no mortality
2. E. brunetti (affects maturing chickens)- uncommon, slow growth, bloody diarrhea, moderate to high mortality
3. E. hagani (any age chicken)- uncommon, no symptoms, maybe water diarrhea, no mortality
4. E. maxima (chicks 3-5 weeks of age)- common, pale skin, bloody/off color droppings, low to moderate mortality
5. E. mitis (any age chicken)- common, slow growth, weight loss, no mortality rate
6. E. mivati (chicks 3-5 weeks of age)- common, slow growth, low mortality
7. E. necatrix (affects maturing chickens)- common, occurs fast, watery & bloody diarrhea, dehydration, moderate to high mortality
8. E. praecox (chicks 3-5 weeks of age)- uncommon, none or slow growth rate, usually no mortality
9. E. tenella (chicks 4-6 weeks of age)- common, occurs fast, pale skin, bloody droppings, moderate to highest mortality

E. tenella is the most aggressive of coccidia species. It can come on rapidly and cause numerous deaths in young and growing chickens. E. tenella is the only coccidia that does not live directly in the intestines. Instead, it infects a chicken’s ceca where it creates enough damage to cause death.

How to Treat Coccidiosis

There are several holistic approaches to preventing or dealing with a cocci outbreak, which I will discuss in another article. For now, we are just going to look at the two drug options available for treating severe cases of cocci. Unfortunately, there have been no natural remedies proven to cure severe cases of coccidiosis.

The two drugs commonly associated with treating coccidiosis are Amprolium and sulfa drugs. Many drugs can be used in low dosages to prevent cocci and in high dosages to treat a cocci infection. It is often helpful to understand the differences between a coccidiostat and coccidiocides when deciphering drug or feed bag labels:

• coccidiostat– allows a trickle infection to occur giving the bird time to build immunity, used to prevent or control cocci infections
• coccidiocides– kill cocci protozoa, used to treat severe infections

Amprolium

Amprolium is the most common drug used for treating coccidiosis in non-commercial chickens. It is added to medicated chick feed in low dosages to help prevent coccidiosis in growing chicks. However, Amprolium can also be bought in a liquid or soluble powder form (Amprol or Corid) to be mixed into drinking water and used as a treatment for severe infections of cocci.

Amprolium works by inhibiting the body’s ability to use thiamin (vitamin B1), which is needed by cocci protozoa to survive. Although it is not 100% affective against all cocci, it does treat most of the common species of cocci. It is a drug that has no meat or egg withdrawal period and is the least likely drug to cause resistance amongst cocci protozoa strains.

You can use Amprolium to treat severe cases of cocci by mixing a 1/3 of an ounce of powder into 1 gallon of water. Give your flock the treated water for 10-14 days (refreshing the water every day) to treat a cocci infection.

However, using Amprolium as a cocci preventative or treatment will cause a vitamin B1 deficiency in your flock’s diet. You will need to give your chicks or chickens a vitamin supplement after using the drug to help them replenish their vitamin levels. Don’t use a vitamin supplement at the same time as the drug so as not to counteract the drug.

Sulfa Drugs (sulfonamides)

Most sulfa drugs come in a powder or liquid form to add to your flock’s drinking water as a treatment for severe cocci infections. Sulfa drugs work by preventing the absorption of folic acid (vitamin B9), another vitamin needed by cocci protozoa to survive. Unlike Amprolium, sulfa drugs do have meat and egg withdrawal periods since the sulfa residue in a chicken’s body can be transferred to the its meat and eggs.

The safest sulfa drugs on the market to use for chickens are Albon or Di-Methox, which have a 5 day meat and egg withdrawal period. Sulmet is another sulfa drug that is strong treatment for cocci, and it has a 10 day withdrawal period. PoultrySulfa is a third sulfa drug option you can use to treate cocci infections. It is a very strong drug and has a 14 day withdrawal period. The strongest sulfa drugs will be the most effective against aggressive species of coccidia (E. necatrix & E. tenella).

Many sulfa drugs contain anti-bacterial properties, which help improve the rate of recovery for a chicken affected by cocci. Always follow the instructions on the drug packaging when administing sulfa drugs. The packaging should supply you with dosage amounts and how long to administer the treatment.

Cautions!

Don’t give sulfa drugs to pullets who are over 14 weeks of age or to laying hens. The drugs can affect laying ability and reproduction.

Sulfa drugs can be toxic if they are used for too long or too much is given in a dosage. Many times the toxic dosage is actually close to the treatment dosage, so poisoning can accidentally occur if a chicken drinks too much of the treated water. Signs of sulfa poisoning include depression, paleness, and slow growth. If administering sulfa drugs in hot weather, when chickens may naturally drink more water, use 1/3 less than recommended dose to prevent sulfa poisoning.

Cocci species can also develop resistance to sulfa drugs, so they are not always effective when used for treating subsequent cocci infections.

Drawbacks to Drugs

As with most drug treatments, there are some drawbacks to using them to treat a cocci infection. Drugs can cause side affects (such as reducing producivity) and even be toxic if consumed in large amounts. You must be especially careful when using sulfa drugs since they can easily be overdosed and cause sulfa poisoning. Amprolium can also be hazardous to waterfowl if it consumed in large quanities, which is why you shouldn’t feed medicated chick started to ducklings or goslings.

Drugs will also surpress a chicken’s immune system. They may even prevent a chicken from developing natural immunity to cocci since the drug is killing off the cocci needed by the body to create an immune repsonse. Lastly, continual usage of drugs as preventatives can lead to drug-resistant strains of coccidia. Using drugs on resistant strains of cocci will be ineffective against the infection.

This overview on how to diagnose coccidiosis in chicks and chickens should give you a better understanding of this common poultry ailment. Coccidia protozoa are present in nearly every environemt where there are chickens. So knowing how to deal with this disease is practically essential to raising a healthy and productive homestead flock. Feeding your flock a balanced diet, using natural supplements, and raising chicks in a natural environement can all help prevent cocci from becoming a problem in your flock!

Don’t miss any other tips for raising a homestead flock! Join our modern pioneer newsletter and get a free copy of our ebook, Raising Chickens Like a Pioneer!

by Alexa