Runting Stunting Syndrome is not merely a problem of slow-growing chickens, but a complex disorder that damages the digestive system, reduces feed efficiency, and threatens the profitability of the farm, making prevention from the early phase of rearing the main key to production success.

Runting Stunting Syndrome (RSS) has long been one of the serious challenges in the modern poultry industry. This syndrome impairs the growth of young chickens, especially broilers, with the main signs being stunting and a growth rate far slower than the normal standard. Although it has been recognized since the 1940s and gained increasing attention as the broiler industry developed rapidly in the 1970s, RSS continues to appear today. This condition is not just a matter of livestock health, but also an economic issue that potentially causes huge losses for farmers.

RSS is a metabolic and infectious problem that primarily attacks the chicken’s digestive system, particularly the small intestine. When the process of nutrient absorption is inhibited, the chicken cannot utilize feed optimally. The impact is not only a stunted body but also a decrease in feed efficiency, an increase in morbidity rates, and the potential failure to achieve target harvest weight. Many field reports indicate that chickens with RSS can have a weight up to 40% lower than the standard at the same age. This condition certainly affects market demand, which requires uniformity and ideal weight. Chickens that are too light are often sold below cost, or even culled because they are considered unprofitable.

Clinically, chickens with RSS display easily recognizable characteristics. Their bodies appear smaller, the color of their skin and beak looks pale, and their feathers often grow imperfectly, appearing dull, or even standing on end. The chicken’s abdomen looks enlarged due to gas accumulation in the intestines, while the feces tend to be watery and contain undigested feed residue. The chickens appear passive, less aggressive in competing for feed, and are in an inferior position compared to others in the same cage. Symptoms begin to become clear when the chickens are six to twenty-one days old, although the disorder process starts in the early days after hatching. In layers, cases are more often found in the pre-laying phase at 12–16 weeks of age and potentially inhibit the achievement of the production age.

When observed anatomically, the changes caused by RSS are very typical. The intestinal surface shows signs of inflammation, intestinal villi shrink or are damaged, leading to very poor nutrient absorption, and the intestines swell due to accumulated gas. The liver experiences degeneration and hemorrhagic spots, a sign of hepatitis arising from toxins and metabolic disorders. Vital organs such as the pancreas, thymus, and bursa of Fabricius appear shrunken, indicating a decrease in metabolic and immune function. This damage is even clearer in microscopic examination, where the intestinal epithelial cells degenerate, villi shrink, and lymphoid organs experience fibrosis. The viruses causing RSS, especially Reovirus, are known to attack cells and damage mitochondria, so the cell’s ability to generate energy decreases drastically. When energy for growth is impaired, the chicken is unable to catch up with normal development, even if nutritional management is subsequently corrected.

This article is an excerpt from the Health column in the November 2025 edition of Poultry Indonesia magazine. Read the full article in the Poultry Indonesia Magazine November 2025 Edition, and for subscriptions or more information, please contact: https://wa.me/+6287780120754 or sirkulasipoultry@gmail.com