Productive Performance of Broiler after Pre and /or Post-hatching Injection of Thyroid and Growth Hormones

A total number of 1340 eggs from Arbor Acres parent breed were used in this study. Eggs were divided into two division according to the incubation relative humidity (48% and 52%). Eggs of each division were than subdivided into ten groups, eggs of 1st, 2nd and 3rd groups were injected with 0.05, 0.10 and 0.15μg eltroxin, respectively, those of the 4th, 5th and 6th groups were injected with 0.05, 0.10 and 0.15 mg Carbimazole, respectively, while eggs of the 7th, 8th and 9th groups were injected with 0.005, 0.02 and 0.04 I.U. growth hormone, respectively. Eggs of the 10th group were injected with distilled water and used as control group. Each group was divided into two divisions, eggs of the first division were injected just before incubation (into the air cell) and those of the second division were injected at the 9th day of incubation period (into the embryonic allantoic cavity). A total number of 960 hatched chicks were randomly selected (24 chicks of cach group), wing banded, individually weighted, vaccinated and standard conditions of management, environment, hygiene and nutrition