A total number of thirty, one day old Hubbard chicks were used in this study. Blood samples were collected three times from each five chickens and periodically at 6, 8 and 12 weeks of age from the onset of the experiment, which extended from one day up to 12 weeks of age. The determination of serum total proteins, protein fractions, IgG concentration and hemagglutination inhibition titre were estimated. The results revealed that, total globulins, Alpha-2 globulin and gamma globulin levels were significantly increased at 8 weeks of age, whereas the A/G ratio showed a significant decrease only as compared with the findings recorded at the 6 weeks of age. However, the level of total proteins, alpha-2 globulin and gamma globulin were highly significant increase at 12 weeks of age, whereas the concentration of total globulins and alpha-1-globulin, showed, a significant increase. Moreover, the level of serum albumin, beta-globulins and hemagglutination inhibition titre showed a non-significant change. Serum immunoglobulin IgG levels showed a highly significant increase at 8 and 12 weeks of age.