How to recognise coccidiosis as a cause of intestinal problems in poultry?

Bloody droppings, lethargy, and sudden losses? Discover how to recognize and confirm coccidiosis in poultry.

Coccidiosis in poultry can be recognized by a combination of bloody or mucous droppings, reduced feed intake, lethargy, and sudden mortality, caused by microscopic parasites of the genus Eimeria that damage the intestinal wall. The condition primarily affects young chicks between one and six weeks of age, but can also affect older birds when infection pressure is high or immunity is low. This article answers the most frequently asked questions about recognizing, distinguishing, and confirming coccidiosis as the cause of intestinal problems in poultry.

Which symptoms specifically indicate coccidiosis in poultry?

Coccidiosis in poultry manifests as bloody, orange, or mucous droppings, followed by sudden mortality, lethargy, feather pecking, and a severely reduced feed intake. The combination of these signs along with visible blood in the litter layer is a strong indication of an active outbreak.

In addition to the striking changes in droppings, the flock often shows clear behavioral changes. Birds withdraw, huddle near the heat source, and stop drinking. The plumage appears fluffy and unkempt. In severe cases, pale discoloration of the skin occurs due to blood loss from the damaged intestinal wall.

It is important to note that the severity of symptoms varies greatly depending on the Eimeria species. Some species cause massive hemorrhaging and acute mortality, while others follow a more insidious course with barely visible external signs but significant production losses. It is precisely this subclinical form that is regularly missed in practice.

How do you distinguish coccidiosis from other intestinal problems in chickens?

Coccidiosis differs from other intestinal problems in chickens in that the droppings almost always contain blood or mucus and the outbreak occurs acutely within a specific age group. Other common intestinal disorders such as necrotic enteritis or dysbacteriosis differ in terms of dropping color, age profile, and histopathological picture.

A practical way to compare is to look at the following characteristics:

Coccidiosis: bloody or orange droppings, acute outbreak, mainly in chicks aged 2 to 6 weeks, high mortality within a short period
Necrotic enteritis: brown, foul-smelling droppings with a strong odor, caused by Clostridium perfringens, often as a secondary infection following coccidiosis
Dysbacteriosis: wet, foamy droppings without blood, gradual onset, linked to feed composition or microbiome disruption
Rotavirus or other viral enteritis: watery diarrhea, no blood, affects all ages, high infectivity

It is also relevant to know that coccidiosis and necrotic enteritis frequently occur together. The intestinal damage caused by Eimeria creates an ideal environment for Clostridium overgrowth. When both conditions are present simultaneously, the damage to the intestinal wall and production is considerably greater.

Which Eimeria species cause the most damage in poultry?

Seven Eimeria species have been described in poultry, of which E. tenella, E. necatrix, and E. acervulina cause the most damage. E. tenella attacks the cecal tissue and leads to severe hemorrhaging, while E. acervulina damages the small intestinal section and significantly reduces nutrient absorption.

Below is an overview of the most damaging species and their location in the gastrointestinal tract:

Eimeria tenella – attacks the cecum, causes bloody diarrhea and high mortality in young chicks
Eimeria necatrix – infects the small intestine, leads to severe tissue damage and sudden mortality
Eimeria acervulina – most common species, infects the upper part of the small intestine, subclinical course but major effect on growth and feed conversion
Eimeria maxima – middle part of the small intestine, orange mucous droppings, negative effect on protein absorption
Eimeria brunetti – affects the lower part of the small intestine and the rectum, can cause severe damage under high infection pressure

In practice, mixed infections with multiple species occurring simultaneously are most common. This makes the clinical picture more complex and the damage to intestinal integrity greater than with a single-species infection.

When is poultry most vulnerable to a coccidiosis outbreak?

Poultry is most vulnerable to coccidiosis during the first six weeks of life, when the developed immunity does not yet provide sufficient protection against high infection pressure in the barn. Periods of stress, heat, feed changes, or high stocking density considerably increase the risk.

The life cycle of Eimeria plays a crucial role. Oocysts survive for weeks to months in the litter and become active as soon as temperature and humidity rise. Wet litter is therefore one of the most important risk factors: it accelerates the sporulation of oocysts and increases the chance of oral uptake by the animals.

Heat stress poses an additional risk. When birds drink and eat less due to high temperatures, the intestinal barrier weakens and resistance decreases. This makes the intestinal epithelium more susceptible to parasitic invasion. Flocks that have recently been vaccinated or have recovered from another infection are also temporarily more vulnerable. A stable intestinal health through betaine can play a supportive role during such periods.

How do you confirm a suspicion of coccidiosis on the farm?

A suspicion of coccidiosis is confirmed by having fecal examination performed via flotation or the McMaster technique, in which oocysts of Eimeria are detected and quantified. Additionally, post-mortem examination of deceased birds provides direct insight into the location and severity of intestinal damage.

In practice, confirmation proceeds in steps:

Clinical observation: assess dropping color, behavior, and mortality of the flock
Fecal sample: collect fresh fecal samples from multiple birds and have them analyzed by an accredited laboratory
Post-mortem examination: have a veterinarian perform a necropsy on deceased or euthanized birds to macroscopically assess the intestinal wall
Histopathology: in cases of doubt, microscopic tissue examination provides definitive information about the species present and the degree of tissue damage
PCR diagnostics: for accurate species identification, relevant for adjusting vaccination programs

An important caveat: the presence of oocysts in the droppings does not automatically prove that coccidiosis is the cause of the clinical signs. A low oocyst count in subclinical infection can still be accompanied by considerable intestinal damage. The combination of laboratory results and clinical picture is decisive for the diagnosis.

What is the impact of coccidiosis on intestinal health and production results?

Coccidiosis damages the intestinal villi and disrupts the barrier function of the intestinal epithelium, leading to reduced nutrient absorption, increased susceptibility to secondary infections, and significant production losses. Even subclinical coccidiosis has a measurable negative effect on growth and feed conversion.

The damage to intestinal integrity in poultry has direct consequences for technical performance. A damaged intestinal wall absorbs amino acids, fats, and minerals less efficiently, resulting in a poorer feed conversion ratio (FCR) and lower daily growth. In broilers, this translates directly into lower carcass weight and reduced breast muscle yield.

In addition to the direct damage, coccidiosis also increases the risk of secondary infections. The damaged intestinal wall offers less resistance to pathogens such as Clostridium perfringens, which promotes necrotic enteritis. Furthermore, the infection disrupts the microbiome balance: the equilibrium between beneficial bacteria such as Firmicutes and harmful pathogens shifts toward dysbiosis, resulting in further inflammatory responses.

In laying hens, coccidiosis leads to a decline in egg production, poorer shell strength, and a higher percentage of secondary eggs. The long-term effects on the persistence of the laying period are also significant when an outbreak is not addressed in time.

How Jodoco helps with intestinal problems and coccidiosis in poultry

At Jodoco, we develop products that actively support the intestinal health of poultry, including during periods of increased infection pressure such as a coccidiosis outbreak. Our approach combines multiple mechanisms of action in one formula, aimed at strengthening the intestinal barrier, supporting the microbiome, and limiting the consequences of stress and infection.

Our drinking water and feed additives for animals provide concrete support for intestinal problems caused by coccidiosis:

Strengthening of tight junctions: natural betaine increases the expression of occludin and claudin-1, making the intestinal barrier more resistant to damage
Antimicrobial action: Grovax combines organic acids, slow-release butyrate, and MCFA (C8, C10, C12), which combat gram-negative and gram-positive bacteria and inhibit secondary infections
Support of osmoregulation: betaine protects enterocytes against osmotic stress and reduces fluid loss in the intestinal lumen, which benefits litter quality
Flexible administration via drinking water: in sick birds, water intake is more reliable than feed intake, allowing our products to be effectively absorbed even during an outbreak
Compatible with a NAE strategy: our products support an antibiotic-free approach and strengthen the natural resistance of the flock

Would you like to know which product best suits the situation on your farm? Contact us and we will help you with a targeted approach to intestinal health in poultry.