Moderately fermentable dietary fiber, especially when combined with stimbiotic (STB) supplementation, can enhance intestinal health, nutrient utilization, and overall perfor-mance in laying hens, although effects depend on fiber type, level, and diet composition. To investigate this, 1,200 Bovans White laying hens (32 weeks old) were assigned to a 2 × 6 factorial experiment with two levels of supplementation (without or with 0.01% STB) and six dietary fiber treatments: Control (corn–soybean), Wheat–High CF, 75:25 wheat–corn, 50:50 wheat–corn, 25:75 wheat–corn, and Corn–soybean–Low CF. The study spanned five 28-day periods, evaluating productive performance, egg quality, and intestinal morphol-ogy. Dietary fiber levels significantly improved feed intake, egg production, egg mass, feed conversion, and intestinal structure, while STB alone had limited effects. Hens fed 75:25 and 50:50 wheat–corn diets consumed more feed, and the highest egg production and mass were observed in birds receiving Control, 75:25 wheat–corn, and Wheat–High CF diets. Egg quality benefited from the fiber–STB interaction, producing heavier eggs with higher yolk pigmentation, thicker shells, and greater Haugh unit and specific gravity. STB supplementation increased jejunal villus width and absorptive area, whereas fiber type affected ileal morphology. In conclusion, high dietary fiber improves performance, egg quality, and intestinal health in laying hens, and supplementation with 0.01% STB further enhances these effects.

Moderately fermentable dietary fiber (with different crude fiber [CF] levels), especially when combined with stimbiotic (STB) supplementation, can enhance intestinal health, nutrient utilization, and overall performance in laying hens, although effects depend on fiber type, level, and diet composition. To investigate this, 1200 Bovans White laying hens (32 weeks old) were assigned to a 2 × 6 factorial experiment with two levels of supplementation (without or with 0.01% STB) and six dietary fiber treatments: Control (commercial diet), Corn–soybean, 75:25 wheat–corn, 50:50 wheat–corn, 25:75 wheat–corn, and Corn–soybean. The study spanned five 28-day periods, evaluating productive performance, egg quality, and intestinal morphology. Dietary fiber levels significantly improved feed intake (p = 0.0029), egg production (p < 0.0001), egg mass (p < 0.0001), feed conversion (p < 0.0001), and intestinal structure (p ≤ 0.05), while STB alone had limited effects. Hens fed 75:25 and 50:50 wheat–corn diets consumed more feed, and the highest egg production and mass were observed in layers receiving Control, 75:25 wheat–corn, and Corn–soybean diets. Egg quality benefited from the fiber–STB interaction, producing heavier eggs with higher yolk pigmentation (p ≤ 0.05), thicker shells (p ≤ 0.05), and specific gravity (p ≤ 0.05). STB supplementation increased jejunal villus width (p = 0.0001) and absorptive area (p = 0.0063), whereas fiber type affected ileal villus width (p = 0.0025) and absorptive area (p = 0.0156). Fiber–STB interaction influences the duodenum villus width (p = 0.0106), crypt depth (p = 0.0011), villus-to-crypt ratio (p = 0.0058), and absorptive area (p = 0.0086), and ileum villus width (p = 0.0011), crypt depth (p = 0.0058), and absorptive area (p = 0.0086). In conclusion, the use of 0.01% STB in diets with high crude fiber levels (25:75 and 75:25 wheat–corn ratios) improves performance, egg quality, and intestinal health in laying hens.