In this feeding trial, a total of 500 Cobb-500 broiler (day-old) chickens were randomly assigned to a control dietary treatment (basal diet only) or supplemented with crushed seeds of coriander (Coriandrum sativum L.), black cumin (Bunium persicum (Boiss.) B. Fedtsch) and ajwain (Carum copticum L.) (at 10 mg/kg each) and exogenous protease (30,000 IU/kg), respectively, in order to assess the effect of the diets on nutrient digestibility, bone strength and gut morphology. The results indicated that the digestibility coefficients of crude protein, crude fat, nitrogen-free extract, calcium and phosphorous were significantly (p < 0.05) higher in protease-treated birds compared to the control. The tibia bone weight was improved (p = 0.03) in Carum copticum, Coriandrum sativum and protease-supplemented birds. Bone length increased (p < 0.05) in protease and Carum copticum fed broilers, while the robusticity index decreased (p < 0.05) in all treatments. Villus length and width decreased (p < 0.05) in Carum copticum and Bunium persicum fed broilers. From findings, it was demonstrated that exogenous protease shows comparatively better results in improving bone quality, ileal digestibility and villus morphology in broilers.