Short-chain fatty acids have been widely used as feed additives to control Salmonella in poultry. Data on the use of butyric acid in poultry are lacking. In this study, powder form and coated butyric acid were compared in their ability to reduce Salmonella colonization of ceca and internal organs shortly after infection of young chickens with Salmonella enteritidis. In the first trial, 4 groups of 25 specific pathogen free layer chickens were given feed either supplemented with powder form butyric acid, coated butyric acid, a combination of powder form and coated butyric acid (all groups received a total of 0.63 g of butyric acid/kg) or nonsupplemented feed. The specific pathogen free layer chickens were orally infected with 10(6) cfu of S. enteritidis. Coated butyric acid significantly decreased cecal colonization 3 d post-infection compared with control chickens, and powder form butyric acid had no effect. To study long-term shedding and colonization of Salmonella in broilers given coated butyric acid as feed additive (0.63 g of active product butyric acid/kg), 10 Ross broiler chickens were infected at d 5 with 10(5) cfu of S. enteritidis and housed together with 40 noninfected broilers. A control group received nonsupplemented feed. The group of broilers receiving coated butyric acid had a significantly lower number of broilers shedding Salmonella bacteria, but cecal colonization at slaughter age was equal for both groups. In conclusion, butyric acid decreases cecal colonization shortly after infection, decreases fecal shedding, and as a consequence, decreases environmental contamination by S. enteritidis-infected broilers. However, complete elimination can probably only be achieved with a combined approach using both hygienic measures and different protection measures, as the broilers still carried S. enteritidis bacteria in the ceca at slaughter age, although at enrichment level.