A timely blood test is essential to detect possible abnormalities in the body. Blood somewhat objectively reflects the state of the internal environment in which all metabolic processes take place. The blood test is one of the most informative laboratory diagnostic tools, which provides essential information about the functional state of various organs and systems of the body. The work aimed to investigate the changes in morphological parameters, protein profile, and activity of aminotransaminases in the blood of turkeys in the presence of keel “namins”. The research was carried out at “Indykat” Ltd. in the village Kadubivtsi of the Lviv region on turkeys of the Big-6 breed on two groups of turkeys, 10 birds each. The turkeys of the control group were clinically healthy, and those of the experimental group had visible clinical signs of “namin” on the keel. The results of the research showed that the number of erythrocytes in the blood of clinically healthy birds was 2.5 ± 0.19 T/l, leukocytes – 21.8 ± 1.36 G/l, hemoglobin content – 90.5 ± 2.54 g/l, and the hematocrit was equal to 29.4 ± 1.44 %. In the presence of “namins” in the blood of turkeys, the number of leukocytes and hematocrit, compared to the control, was higher by 15.2 and 3.8 %, respectively, and the number of erythrocytes and hemoglobin content was lower by 16.1 and 11.3 %. Analyzing the leukogram of the blood of the turkeys of the research group, the appearance of basophilic leukocytes and young neutrophils was established, the number of which was 1.1 ± 0.08 and 0.2 ± 0.01 %, respectively. Compared to the control, the number of rod-shaped and segmented neutrophils was higher by 1.3 and 6.3 %, monocytes by 16.3 %, and eosinophils and lymphocytes were lower by 1.3 and 16.8 % and amounted to 6, 3 ± 0.27 and 41.1 ± 2.41 %. The level of total protein in the blood of birds in the pectoral muscles that developed and formed “namins” was 26.4 ± 1.35 g/l and was 6.7 % lower than that of the experimental group. In the presence of “namins” on the keels of turkeys, a 4.4 % higher level of globulins, which perform a protective function, and a 17.1 % lower amount of albumins were found. The pathological process that developed in the pectoral muscles of turkeys led to an increase in the activities of alanine aminotransferase and aspartate aminotransferase in the blood of turkeys to 32.4 ± 1.23 and 314.2 ± 14.2 units/l, which was more significant than indicators of the control group by 8.6 and 8.3 %, respectively.