The most common intestinal pathogens in poultry in 2026 are Eimeria species (causative agents of coccidiosis), Clostridium perfringens (causative agent of necrotic enteritis), and certain strains of Salmonella and Campylobacter. These microorganisms are responsible for the majority of economic damage in the poultry sector worldwide. In this article, we answer the most frequently asked questions about intestinal pathogens in chickens and how to recognize, prevent, and address them.
Which intestinal pathogens cause the most damage in poultry?
The intestinal pathogens that cause the most damage in poultry are Eimeria species, Clostridium perfringens, Salmonella and Campylobacter. Each of these pathogens compromises intestinal integrity, disrupts nutrient absorption, and increases mortality or culling. The economic impact is enormous: poor feed conversion, slower growth, and higher treatment costs.
Eimeria is a unicellular parasite that directly damages the intestinal wall and severely impairs nutrient absorption. Multiple Eimeria species can infect poultry, of which E. tenella, E. acervulina and E. maxima are the most damaging for broilers.
Clostridium perfringens is a bacterium that, under certain conditions, produces toxins that break down the intestinal wall. This leads to necrotic enteritis, a condition that can rapidly become fatal. Salmonella and Campylobacter are not only harmful to the animals themselves, but also pose a risk to public health through the food chain.
- Eimeria spp.: parasitic infection, damages intestinal villi, causes coccidiosis
- Clostridium perfringens: bacterial infection, produces necrotizing toxins
- Salmonella spp.: bacterial infection, systemic impact and food safety risk
- Campylobacter spp.: bacterial infection, public health risk
- Rotavirus and reovirus: viral intestinal pathogens, particularly in young chicks
How is coccidiosis and necrotic enteritis recognized in chickens?
Coccidiosis is recognized by bloody or mucoid droppings, reduced appetite, lethargy, and stunted growth. Necrotic enteritis is characterized by sudden mortality, dark discoloration of the intestinal wall, and a sharp rise in losses within a short period of time. Both conditions require rapid action.
Symptoms of coccidiosis in chickens
In coccidiosis in chickens, the clinical signs depend on the Eimeria species affected and the part of the intestine that is infected. The most notable symptoms are:
- Bloody or orange discoloration of the droppings
- Severely reduced feed and water intake
- Lethargy, ruffled feathers, and huddling behavior
- Stunted or arrested growth in broilers
- Increased mortality, particularly in young animals
At post-mortem examination, damaged intestinal villi, hemorrhages in the intestinal wall, and in severe cases massive cell death in the intestinal epithelium are observed. The diagnosis is confirmed by microscopic examination of intestinal contents or droppings.
Symptoms of necrotic enteritis in chickens
Necrotic enteritis often follows an acute course. Animals that appeared healthy the evening before are found dead the following morning. At post-mortem examination, the typical “wet cardboard” odor of the intestinal contents is noticeable, along with a greenish-brown discoloration and detachment of the intestinal mucosa. Subclinical forms are more difficult to recognize but cause significant production losses through deteriorated feed conversion and reduced growth.
What are the risk factors for intestinal infections in poultry houses?
The main risk factors for intestinal infections in poultry houses are high stocking density, poor litter quality, abrupt feed changes, heat stress, and a disrupted gut microbiome. When several of these factors coincide, the risk of an outbreak of coccidiosis or necrotic enteritis increases considerably.
Heat stress is a particularly underestimated risk factor. When the temperature in the house rises, water intake increases while feed intake decreases. This disrupts the osmotic balance in the gut and weakens the barrier function of the intestinal epithelium. Pathogens such as Clostridium perfringens take advantage of this weakened state to multiply.
The composition of the feed also plays a major role. Diets with a high proportion of wheat or barley contain more non-starch polysaccharides (NSP), which increase the viscosity of the intestinal contents. This creates ideal conditions for the growth of harmful bacteria. An abrupt transition to a different feed also temporarily disrupts the microbiome balance, providing an opening for opportunistic pathogens.
Additional risk factors include:
- Insufficient cleaning and disinfection between flocks
- Contaminated drinking water or feed
- Stress from transport, vaccination, or environmental changes
- Imbalance in the ratio of beneficial to harmful gut bacteria (dysbiosis)
- Antibiotic resistance due to excessive use in the past
How do natural ingredients protect the gut health of poultry?
Natural ingredients such as betaine, organic acids, medium-chain fatty acids (MCFA), and butyrate protect the gut health of poultry by strengthening the barrier function, inhibiting harmful bacteria, and supporting microbiome balance. They offer an effective alternative or supplement to antibiotics, fitting within a “No Antibiotic Ever” strategy.
Betaine plays a central role in this. As an osmoprotectant, betaine reduces epithelial stress in intestinal cells, particularly during heat stress or infection. It strengthens tight junction proteins such as occludin and claudin-1, making the intestinal wall less permeable to pathogens. Scientific research shows that betaine increases villus height and reduces crypt depth, leading to a larger absorption surface and better nutrient utilization. More information about the mode of action of betaine can be found on our page about betaine in animal nutrition.
Organic acids lower the pH in the gut, thereby inhibiting the growth of gram-negative and gram-positive bacteria. Butyrate, a short-chain fatty acid, strengthens intestinal integrity and reduces inflammatory responses in the intestinal mucosa. MCFA (such as caprylic acid C8, capric acid C10, and lauric acid C12) have a direct antimicrobial effect and are particularly effective against Clostridium perfringens and Salmonella.
Essential oils such as oregano and garlic have been shown to positively influence microbiome balance and support eubiosis in the gut. Yeast cell walls containing beta-glucans and MOS bind pathogens and stimulate the immune system. More information about our drinking water and feed additives for animals can be found on our website.
When is veterinary treatment necessary for intestinal problems in poultry?
Veterinary treatment is necessary when mortality suddenly increases, clinical signs of bloody droppings or mass mortality occur, or when preventive measures have insufficient effect. If necrotic enteritis or severe coccidiosis is suspected, one should not wait, as the situation can deteriorate rapidly within 24 to 48 hours.
A veterinarian can identify the exact pathogen based on post-mortem examination and laboratory testing and draw up a targeted treatment plan. In countries with a strict antibiotic policy, it is important to first determine resistance profiles before deploying an antibiotic. This prevents unnecessary use and protects the effectiveness of existing agents.
Preventive monitoring is at least as important as curative treatment. Regular fecal analyses, tracking weekly mortality figures, and observing behavior and feed intake provide early insight into emerging problems. A veterinary gut health check two to three times per round is a worthwhile investment for intensive broiler operations.
Signals that require immediate veterinary attention:
- Daily mortality above 0.5% of flock size
- Bloody or highly mucoid droppings in multiple animals simultaneously
- Sudden drop in feed or water intake of more than 15%
- Visible neurological symptoms or loss of coordination
- Strong odor of intestinal contents at post-mortem examination combined with green discoloration
How Jodoco helps with gut health in poultry
At Jodoco, we develop scientifically substantiated products that support the gut health of poultry at multiple levels. Our approach combines proven effective ingredients in one formula, so that livestock farmers do not have to choose between efficacy and sustainability.
Our product Grovax is a liquid combination of organic acids, slow-release butyrate, MCFA, and essential oils. It combats both gram-negative and gram-positive bacteria, strengthens intestinal integrity, and fits fully within an antibiotic-free strategy. Grovax can be applied via drinking water or feed and dissolves completely without clogging pipes.
What sets us apart is our holistic approach to gut health. Rather than targeting a single mechanism of action, we combine:
- Betaine as an osmoprotectant and tight junction strengthener
- Organic acids for pH reduction and bacterial inhibition
- Butyrate for intestinal integrity and anti-inflammatory action
- MCFA for direct antimicrobial activity
- Yeast cell walls for immune stimulation and pathogen binding
- Essential oils for microbiome support and eubiosis
Would you like to know which products best suit your flock and housing situation? Contact us and our specialists will be happy to assist you with personalized advice.
