The poultry industry has developed rapidly in response to the increasing global demand for high-quality animal protein. However, modern poultry production faces several challenges, including increasing feed costs, antibiotic resistance, environmental pollution, heat stress, and the need to improve feed efficiency. Consequently, recent research has increasingly focused on precision nutrition, intestinal health, gut microbiome modulation, alternative feed ingredients, and smart technologies. This review summarizes recent advances in these areas, with particular emphasis on the relationship between dietary interventions, gut microbiota, intestinal barrier integrity, immune function, and productive performance in broiler chickens. Recent evidence indicates that probiotics, prebiotics, synbiotics, postbiotics, fermented feeds, and alternative protein sources may improve gut health and contribute to sustainable poultry production. In addition, heat stress can alter intestinal microbiota and compromise intestinal integrity, highlighting the importance of nutritional and management strategies for maintaining gut function under challenging environmental conditions. The integration of precision nutrition with artificial intelligence, sensors, and computer-vision technologies represents another promising direction for modern poultry production. Overall, future poultry systems are expected to increasingly integrate nutrition, microbiome management, environmental monitoring, and artificial intelligence to improve productivity, animal health, welfare, and sustainability.