The experiment was carried out on 6-week-old Big-6 turkey hens receiving 1,2,4-triazole or 5-oxo-1,2,4-triazyne derivatives as additives to drinking water for ten weeks. The aim of the study was to determine the influence of the tested compounds on some immunological and haematological parameters of blood and on performance of turkey hens. The results showed that the examined substances did not significantly affect the immune response of turkey hens, although all immunological parameters in the group receiving 5-oxo-1,2,4-triazyne were slightly better than in the control group. Moreover, the 5-oxo-1,2,4-triazyne supplement caused an increase in the RBC count, Ht and Hb levels. Administration of both tested derivatives slightly improved the performance of the birds.