They were 100 in No., floor reared in a closed house in 1 site, (42-47 day rearing cycle), 90 of them were vaccinated by 0.5 cm³ S/C injection in the lower back of neck with the 2 commercial vaccines and the remaining 10 of them were not vaccinated along all the experiment to monitor the Maternal Antibodies coming from their vaccinated breeders. They were vaccinated at 7, 10 and 12 days old and the serum samples were collected 14 day post-vaccination. We used the HA and HI tests to calculate the (HAUs) of the required test Ag, to titrate the collected serum samples respectively and then calculate the G.M.T. values. The results obtained from this study revealed that: the Maternal Immunity of those broiler chickens were firstly high to moderate, (5.9) at 1 day old, low at 7 and 10 days old, (3.8 -1.8), fainting at 12 days old, (1.1) and completely disappeared at 12 days old, (0).The usage of the homologous vaccine,H5N1,gave HI-titers which were always higher and better than the heterologous vaccine, H5N2 at the 3 vaccination ages:{ 7} – {10}  - {12} days: { 4.8 , 4.9 , 5.9 and 6.5} –{ 5.9 , 6.1 , 6.4 and 7} – { 6.8 , 7.1 , 7.7 and 8} respectively using the homologous test antigen and also were higher and better than the heterologous vaccine,H5N2 using the heterologous test antigen at also the 3 vaccination ages:{7} – {10} – {12} days : { 4.1,4.5,5,and 5.01 } – { 4.6,4.8,4.9 and 5.1 } – { 5.3,5.6,6.5 and 7 } respectively. The percentages of the AI protective HI-titers obtained from usage of the homologous vaccine,H5N1 were higher than those obtained from the heterologous vaccine,H5N2 using the homologous test Ag at the 3 vaccination ages: { 7 – 10 – 12 days }: { 78.3 – 98.3 – 100 % } for the H5N1 compared to { 68.3 – 80 – 98.3 % } for the H5N2. Also these percentages were higher for the homologous vaccine, H5N1 than the heterologous one, H5N2 using the heterologous test Ag: {53.3 – 61.7 – 90 %} for the H5N1 compared to {35 – 46.7 – 75 %} for the H5N2. Usage of the homologous test Ag always gave HI-positive titers and percentages of the AI protective HI-titers which were both always higher than usage of the heterologous test Ag, (results – table 10 and fig. 10). The results also revealed that the best age of vaccination against AI for the broiler chickens is 12 days old for the homologous,H5N1 and heterologous,H5N2 vaccines.