This study evaluated the effects of dietary supplementation with Prebiotics, Probiotics, and Eubiotics on carcass characteristics and the immune response to Newcastle Disease Virus (NDV) in broiler chickens. A total of 200 broilers were assigned to five treatment groups: a negative control (fed on basal feed), a positive control (fed on basal feed + 10% Olaquindox), Prebiotics (Mannan-oligosaccharide + Fructo-oligosaccharide), Probiotics (Lactobacillus acidophilus + Bacillus subtilis), and Eubiotics (synergies). At 42 days of age, key Carcass parameters were assessed and the Immune responses were assayed using the hemagglutination inhibition test on days 7, 14, 28, and 42. Data were analysed using R- software with One-way Analysis of Variance followed by Least Significant Difference tests for pairwise comparisons. The Eubiotics group demonstrated the highest live weight and dressed weight, significantly outperforming other groups (p < 0.05). Regarding immune response, the Eubiotics group recorded the highest Geometric Mean Titer by days 14, 28, and 42, significantly higher than the negative control group (p < 0.05) which consistently showed the lowest titers. These results indicate these additives, especially Eubiotics can enhance both carcass traits and systemic immunity to NDV, supporting their potential as effective alternatives to Antibiotic growth promoters in broiler production systems.