The gut of an animal is a complex environment inhabited by various bacteria that interact among themselves and with the host, and govern its overall health. The pathogenic bacteria in the gut compete with other good colonizers and the host on different paradigms, causing alterations in the gut environment. They cause damage to the gut epithelium and affect feed digestion, leading to infections. Treatment of these pathogens requires antibiotics, which, unfortunately, sooner or later lead to resistance development, with a high risk of cross-contamination to humans. In addition, antibiotics are the most preferred feed supplement for poultry growth improvement and have been indiscriminately used for decades, intensifying the problem. This has forced scientists to search for alternative feed supplements. The most successful alternatives, such as probiotics and prebiotics formulations, are as effective as antibiotics in promoting improved gut health. However, pathogenic bacterial infections still remain a problem, and antibiotic use is needed. Therefore, the focus is shifted toward phage therapy, where bacteriophages, alone or in cocktails, exterminate the pathogen load. Therefore, in this chapter, we discuss the implications of phage therapy in poultry settings and how they have been successfully used, either alone or better as a cocktail, in eliminating pathogenic bacterial load, thereby decreasing our reliance on antibiotics.