A total of 600 day-old broiler chicks (Ross 308) confirmed for the absence of Salmonella were randomly allocated to five treatments each with 10 replicates: negative control (basal diet only); positive control (basal diet) + infected with Salmonella; T1, Salmonella infected + avilamycin; T2, Salmonella infected + Bacillus subtilis (ATCC PTA-6737; 2 × 107 CFU/g) and T3, Salmonella infected + B. subtilis (DSM 172999; 1.2 × 106 CFU/g). The results revealed that feed intake (FI) and body weight (BW) were significantly (p < 0.01) lower in T1 compared to T2. The feed conversion ratio (FCR) was significantly (p < 0.01) lower in T2 and T3 compared to other treatments. Similarly, the performance efficiency factor (PEF) was also significantly (p < 0.01) higher in T2 and T3 compared to positive control. Villus height was significantly (p < 0.01) higher in T2 compared to all other treatments. However, villus width and surface area were significantly (p < 0.01) higher in T1. In conclusion, dietary supplementation with B. subtilis improved growth and intestinal health by reversing the negative effects of Salmonellosis.