The objective of the present study was to determine the effect of the stocking density on health condition, haematology, immune response and application of medicaments in male meat turkey flocks reared under field conditions. Three different stocking densities namely 25, 48 and 58 kg/m² were compared. The stocking density was calculated according to expected body weight at slaughter. Clinical signs, treatments, daily weight gains and mortalities were recorded. In addition blood samples were collected from each group at week 7, 12, 16 and 20 for haematological and serological investigations. The results revealed that the stocking density in all groups and farms didn't influence the frequencies and durations of the treatments. The haematological results showed that there is no stocking density cause significant difference of hematocrit, red blood cells count, hemoglobin, mean corpuscular volume (MCV), mean corpuscular hemoglobin amount (MCH), mean corpuscular hemoglobin concentration (MCHC), thrombocytes count, total leukocytes count and differential leukocytes. Also no significant difference could be determined by the calculation of Heterophils/Lymphocytes ratio, which is used as stress indicator. The immune response to applied vaccines such as Newcastle disease (ND) and/or to field infections with avian metapneumovirus (AmPV) and Ornithobacterium Rhinotracheale (ORT) were measured at several points using ELISA for ND and for TRT and ORT as well as haemagglutination inhibition test. The obtained results showed that there were no stocking density specific differences. On the other hand the daily weight gain on both farms was slightly higher in the 25 kg/m²-groups compared to other groups.

Key words: Haematology, Immune response, Stocking density, Stress, Turkey