Finding The Best Method To Vaccinate Against Infectious Bronchitis And Infectious Bursal Disease In Erbil City

240 chicks of Cobb broiler breed divided in to 4 groups (60 bird/group) as follow: Group1(control group) which vaccinated just against Newcastle Disease (ND) with Lasota strain ( Intervet SP) via drinking water (DW) at 10, 20 and 30 days of age. Group 2 (T1) was vaccinated against ND as in control group plus coarse spry vaccination against Infectious (IB ) with MA5 strain( Intervet SP) at one day of age and drinking water vaccination against Infectious Bursal Disease (IBD) with D78 strain (Intervet SP) at 7 and 14 days of age respectively , while Group 3 (T2) was vaccinated against ND as pervious groups plus day old coarse spry vaccination against IB with MA5 strain then IB strain 4/91( Intervet SP) by DW at 17 days old plus vaccination against IBD strain D78 via DW at 7 and 14 days of age respectively. Group 4 (T3) ND vaccination as group 1 plus day old IB strain4/91 vaccination ( coarse spray) and IBD strain D78vaccination via DW at 7 and 14 days old. Blood samples at day old 35 days old checked by ELISA for Abs titer of IB , IBD ND. The results of study indicate that G2(T1) show best antibody titer against IB using strain MA5 via coarse spray at one day of age , also G2(T1) show better IBD immune response when compared with titers of antibody of other groups , that means the method of vaccination and the strain used will induce better protection level against IB and IBD depending on level of maternal Abs for IBD .