Salmonella infection represents a significant public health threat, particularly within the poultry industry, due to its widespread prevalence and potential for contamination. The rise of antibiotic-resistant Salmonella strains has exacerbated this challenge, making the need for alternative control strategies, such as bacteriophage therapy, increasingly urgent. This study aimed to isolate Salmonella strains from poultry farms in six Egyptian governorates and characterize their antibiotic resistance profiles. The strains were further identified using both biological and molecular methods, and their antibiotic susceptibility was evaluated. Bacteriophages specific to Salmonella were isolated, characterized by transmission electron microscopy, and encapsulated in alginate beads for enhanced stability. The efficacy of these encapsulated phages was assessed In Vitro through stability and bactericidal assays, as well as In Vivo via a controlled study involving infected poultry groups. Eighteen Salmonella strains were identified, several of which demonstrated multi-drug resistance, particularly to commonly used antibiotics, such as chloramphenicol and kanamycin. Phage Sal-1, a Myovirus with high specificity against Salmonella, was successfully isolated and encapsulated. In Vitro, encapsulated phages displayed robust stability and effectively lysed the Salmonella strains. In Vivo, phage-treated poultry exhibited significant reductions in bacterial colony-forming units (CFU), especially in water-based phage treatments, which achieved reductions to 10² CFU, compared to 10⁴ CFU in feed-treated groups. Phage-treated groups showed no mortality, and organ histology was comparable to healthy controls, unlike the severe pathological changes observed in untreated and partially recovered antibiotic-treated groups. In conclusion, encapsulated phage therapy proved more effective than antibiotics, both in terms of efficacy and overall systemic recovery. This study underscores the potential of phage encapsulation as a sustainable alternative to antibiotics in combating Salmonella infections in poultry.