This study investigated the effects of a duo-strain probiotic (DSP) consisting of Enterococcus faecium and Streptococcus thermophilus, administered via a novel premix-spray method, on the growth, digestion, and gut health of broiler chickens. A total of 360 one-day-old Plymouth Rock chicks were divided into two groups: a control group (CG) receiving a soy-corn based diet and an experimental group (DSP) receiving a diet supplemented with 0.5% DSP. The results showed that DSP significantly improved the specific growth rate (SGR), survival rate (SR), and body weight gain (BWG) while decreasing the feed conversion ratio (FCR). DSP also enhanced enzymatic digestion (protease, amylase, lipase, and trypsin) and antioxidant potential (SOD, MDA, and catalase) in broilers compared to the CG. The DSP treatment significantly increased microvillus height in the duodenum and jejunum but had no notable effects in the ileum. The DSP diet increased the relative abundance of Ruminococcaceae and Faecalibacterium, leading to better management of diarrhea and reduced presence of E. coli compared to the control diet. Additionally, including probiotics in the basal diet reduced levels of H₂S, CO₂, NH₃, and CH₄. The study suggests that the new spray-drying approach with these strains has potential for supplementing probiotics in poultry feed processing, and including DSP in broiler chicken diets has beneficial effects. The results indicate that DSP improved growth performance, digestion, antioxidant activity, and gut health in broiler chickens. The study also found that DSP increased the diversity of the intestinal microbiota, with a significant reduction in the percentages of Cynaobacteraeota and Bacteroidetes phyla compared to the CG. The DSP treatment significantly increased the abundance of acid-producing bacteria, specifically Ruminococcaceae in the cecum of DSP broilers. The study concluded that DSP supplementation had positive effects on broiler growth, digestion, and gut health, and that the new spray-drying method is a viable approach for incorporating probiotics into poultry feed.This study investigated the effects of a duo-strain probiotic (DSP) consisting of Enterococcus faecium and Streptococcus thermophilus, administered via a novel premix-spray method, on the growth, digestion, and gut health of broiler chickens. A total of 360 one-day-old Plymouth Rock chicks were divided into two groups: a control group (CG) receiving a soy-corn based diet and an experimental group (DSP) receiving a diet supplemented with 0.5% DSP. The results showed that DSP significantly improved the specific growth rate (SGR), survival rate (SR), and body weight gain (BWG) while decreasing the feed conversion ratio (FCR). DSP also enhanced enzymatic digestion (protease, amylase, lipase, and trypsin) and antioxidant potential (SOD, MDA, and catalase) in broilers compared to the CG. The DSP treatment significantly increased microvillus height in the duodenum and jejunum but had no notable effects in the ileum. The DSP diet increased the relative abundance of Ruminococcaceae and Faecalibacterium, leading to better management of diarrhea and reduced presence of E. coli compared to the control diet. Additionally, including probiotics in the basal diet reduced levels of H₂S, CO₂, NH₃, and CH₄. The study suggests that the new spray-drying approach with these strains has potential for supplementing probiotics in poultry feed processing, and including DSP in broiler chicken diets has beneficial effects. The results indicate that DSP improved growth performance, digestion, antioxidant activity, and gut health in broiler chickens. The study also found that DSP increased the diversity of the intestinal microbiota, with a significant reduction in the percentages of Cynaobacteraeota and Bacteroidetes phyla compared to the CG. The DSP treatment significantly increased the abundance of acid-producing bacteria, specifically Ruminococcaceae in the cecum of DSP broilers. The study concluded that DSP supplementation had positive effects on broiler growth, digestion, and gut health, and that the new spray-drying method is a viable approach for incorporating probiotics into poultry feed.