This study aimed to assess the effect of watery supplementation of probiotic and/or apple vinegar on productive and physiological performances of broiler chickens (Ross 308) reared under high stocking density. Three hundred thirty-six unsexed one-day-old broiler chicks were randomly distributed to eight different treatments (3 replicates each) as follow: T1: Negative control (low stocking density (LSD) 12 birds/m2; basal diet with no studied additives in drinking water), T2: LSD + probiotic, T3: LSD + apple vinegar, T4: LSD + probiotics + apple vinegar, T5: Positive control (high stocking density (HSD), 16 birds/m2 ; basal diet with no studied additives in drinking water), T6: HSD + Probiotics, T7: HSD + apple vinegar and T8: HSD + probiotics+ apple vinegar. Probiotic mixture or/and apple vinegar were provided at a dose of 0.5% in drinking water. The body weight (BW), body weight gain (BWG), feed intake (FI) and feed conversion ratio (FCR) were measured every growth phase until the end of the study at 35 day of age. Also 6 birds of each treatment were used to evaluate carcass traits. Results revealed that administration of probiotics individually or in combined with apple vinegar significantly increased BW, BWG and FI, with a decreased FCR at grower (21 days of age) phase and market age (35 days of age), while apple vinegar additive groups had the lowest BW, BWG and FI, with increased FCR in both tested stocking density. In addition, enhanced carcass yield, some carcass parts (breast and thigh), blood constituents and beneficial bacteria count in small intestine of broilers provided by additives suggested. In conclusion, this study proves valuable effects of probiotic and apple vinegar on growth performance, carcass traits, and microbiological measurements at grower and finisher phases of broilers raised under high stocking density.