The optimal physiological development and productivity of poultry depends on the intake of essential macroand microelements at levels that ensure the safety and quality of the resulting products (meat and eggs). It is important to note that both a lack and an excess of elements can lead to organ and system dysfunction. For instance, even small doses of bromine can cause hepatocyte dysfunction and disruptions to the endocrine and genitourinary systems. Additionally, the ability of these elements to accumulate in eggs and meat makes the products potentially dangerous for human consumption. Our work aimed to investigate the blood leukocyte profile of laying hens under subchronic intake of sodium bromide with feed and calculate integral leukocyte indices that allow assessing the state of the immune system and the degree of endogenous intoxication of the body. We also aimed to determine the strategy for further therapeutic or preventive measures. It was found that the intake of sodium bromide (by bromine) in the body of laying hens for 28 days in doses of 10.0 mg/kg, 50.0 mg/kg, and 250.0 mg/kg of feed leads to a significant increase in the Krebs index, leukocyte intoxication index, leukocyte shift index. This indicates changes in the functional activity of the immune system with the activation of the humoral immune system and decompensation of endogenous intoxication caused by the toxic effects of bromine. The significant decrease in the leukocyte index, neutrophil-monocyte ratio index, lymphocyte-monocyte ratio index, allergy index, and immunoreactivity index indicates a disruption in the interaction between the affective and effector links of immunity. This could potentially lead to cytokine deficiency, a reduction in the level of phagocytic defense, and an increased risk of immediate hypersensitivity.