A total of 38 chicks 20 weeks of age were taken by randomfrom a basic population of 300 chicks of two native breeds, the Fayouml (FF) and the Dandarawi (OD) (150 chicks oath). The chikckens were injected at hatch by Thyroxine Sodium (T4) as 1st treatment, by Carbimazole (goitrogenic drug) as a 2nd treatment, and by distilled water as a con‌trol, to study the effect of Hypo- and Hyper Thyroidism on weight of some Endocrine Glands (Thyroid, Pituitary, Adrenal) and some carcass quality. Correlation coefficient values were estimated between Thyroid and each of Pitiutary and Adrenal. Correaltion coefficent values betwwen ecible meat of careasss and each of Thyroid gland weight, Adrenal gland weight and Pitiutary gland weight values were also estimated. Results obtained indicated that, correlation coefficient value be‌tween thyroid and pititutary gland weights was high in Fayoumi male than female. The vice versa was noticed with Dandarawi breed. Thyroid gland weight showed a highly positive correlation with the adrenal gland weight in both male and female chicks of the two breeds under study. Positive correlation coefficient value was found between thyroid gland weight and edible meat weight of the carcass of either male and female chicks of the two breeds as a result of applying experimental hypo and hyperthyroidism with different rates depending on breed and sex of the chicks. However, these correlation coefficent values were in‌significant magnitude. Correlation coefficient value between adrenal gland weight and weight of edible meat of both Dandarawi and Fayoumi males was in‌creased as a result of experimental hypothyroidism. Edible meat weight was found to be negatively correlated with the weight of the Pitiutary gland.