The first aim of rabbits' diets formulation is to create a low-cost ration that meets the nutritional requirements of fattening rabbits. Seventy two weanling rabbits (42-day old) of NZW breed were utilized in 4x2 factorial arrangements. Treatments were carried out to evaluate the potential of including basil and fennel hay in rations of weanling NZW rabbits at four levels (0.0, 25%, 50% and 75%) as a substitute for alfalfa hay with (0.5 g/kg) or without a synbiotic. Seventy two broiler rabbits were divided to eight treatments, three replications each. Eight rations were formulated and fed to broiler rabbits from 42 to 91 days old. Experimental weaning rabbits were placed under the same managerial conditions and comparable veterinary. The response of broiler rabbits was investigated as growth rate, carcass traits and blood parameters. Replacing dietary alfalfa hay with BH and FH up to 75% produced beast effects on growth rate of broiler NZW rabbits than the basal diet one, regardless of dietary synbiotic-fortification. Analogously, broiler rabbits had fed the synbiotic-enriched diets had positive effects growth performance to that of the basal diet one. Feeding the BH&FH-rations significantly improved total edible parts and carcass yield but decreased the abdominal fat of broiler rabbits. Synbiotic added-diets had useful effects on the percentages of CY, TEP and AF of broiler rabbits. Neither dietary BH&FH levels nor added synbiotic significantly decreased of blood plasma constituents measured herein such as TRG, CHO, vLDL and LDL-C and significantly increased of Alb. and HDL-C. Dietary BH&FH levels with the addition of synbiotic interactions had no significant effects for all criteria measured. Raldala concludes that there is a possibility of replacement of alfalfa hay by BH&FH in growing rabbits' diets up to 75% with significant productive performance and characteristics of carcass; Also, the addition of synbiotic (0.5gm/kg diet) led to improved rabbit growth, carcass yield and total edible parts% but decreased AF percentage.