This study was done in a private field in Al Anbar governorate. 150 bird of ROSS 308 type had been used in this experiment, were divided into five treatments. Each treatment contains thirty bird distributed into three replicates with ten bird in each one of them. The chicks were fed on ration. Contains different percentages of Thyme 0, 0.2, 0.4, 0.6, and 0.8) % in two stages starting with primary ration at the age of 1 day to 28 days or the first stage. The second stage Finishing ration staring with 29 days until the end of the experiment. Some criteria of blood, the levels of AST, ALT and ALP enzymes and some internal organs such as liver, heart and gizzard were studied. The results showed significant increase of 0.8% rate of Thyme in each of RBC number, Hb and PCV with noticeable Improvement in AST, ALT and ALP. In addition, there was an improvement in triglycerides TG at the rate of 0.2% Thyme and in cholesterol at all the rates of Thyme especially T3. The rates of blood protein also raised in all Thyme treatments. T4 had the best results without any significant differences in the rational weight of the heart and gizzard, but the rational weight of the liver had been raised in T2 in the Thyme of 0.2%. Thus, we concluded that using of Thyme with 0.2% and 0.4% had improved significantly all the studied criteria.