Chicks were fed a starter ration from one to 21 days of age, and a finisher ration from 22–42 days of age (Table 1). All rations were formulated in accordance with the requirements recommended by the strain guide. Random samples were taken from each starter and finisher rations for proximate analysis using the procedure described by AOAC (1990). The ingredients used in formulating the starter and finisher rations were mixed together using a mixer type: unimex 1000 STRA 591198 (Skiold Saby-Denmark). Crushed NSS purchased from the local herbal market were added in a level 0.075 with 0.06% lasalocid Na or 0.025% 3-nitro to a part of the basal ration and mixed together using the same mixer in order to form the second and fourth experimental groups. Meanwhile, 0.05% of bacitracin methylene disalicylate (BMD)
was added with 0.06% lasalocid Na or 0.025% 3-nitro and mixed with other parts of the basal ration in order to form the first and the second experimental groups. The remaining partof the basal rations was used without any addition and served as a control group.