Eleven weeks old white leghorn male chicks with single comb were injected under the subcutaneous mear the neck with total 2㎖ of synthetic estrogen solution which contained 27㎎ of diethylstil bestrol (D.E.S.), and 3㎎ of euvestin, a derivative of D.E.S. in 1㎖ of aqueous suspension. In addition to the treatment with D.E.S., both thiouracil (0.01% in the ration) and thyroprotein (0.01% in the ration) were fed for 5 weeks, weight gains and the effect on each organs weight in these three group were compared with the control. The results are as follows 1. Statistical significance were P$lt;0.01 in body weight gains among the treatments. The hormone treatment caused growth stimulation about 20% in three injected groups but there were no significant differences between thiouracil group and thyroprotein group. 2. Weight of comb and testis was remarkably reduced (P$lt;0. Ol) by het treatment of hormone solution. Testis weight was showing no significance between neighbouring groups but comb weight showed significant differences between D.E.S. group and thyroprotein group. 3. Weight of liver showed significance with P$lt;0.01 among the each groups, and was showing no significance between the D.E.S. group and thyroprotein group. 4. The abdominal adipose leaf developed remarkably P$lt;0.01 between each group, it was the most ,striking in the D.E.S. group, followed by the thyrotein group, which was 6 times as much as the weight of the control. 5. The liver moisture content was reduced by injection of D.E.S. The liver fat content showed notable difference P$gt;0.01 among the groups and was increased in order, thiouracil, and thyroprotein group The liver fat content in the D.E.S. group was 2 times as much as the control In the muscle, fat content was Slightly increased in the D.E.S. group but no chance was shown in the other group.