This paper highlights the study results on the usage effectiveness of the domestic complex probiotic preparation Immunoflor developed by PC KROS Farm LLC on Dekalb White egg cross chickens in the production of edible eggs. The work was carried out in the conditions of the agricultural production cooperative "Gornomariyskaya Poultry Farm" of the Republic of Mari El. During the experiment, it was found that eggs from laying hens with the highest weight and more close to the ideal shape were obtained in the 1st and 2nd experimental groups. Indicators of weight, elastic shell strain, albumen index were higher in the experimental groups relative to the control. By the end of the productive period, the yolk index was higher in the 1st and 2nd experimental groups than in the control by 0.12 and 0.7%, respectively. An increase in the albumen height and the indicator of Haugh units was noted in the eggs of the 1st and 2nd experimental groups relative to the control. It was found that egg mass loss decreased when they were stored for 14 days. Thus, the weight of eggs increased and their morphological indicators improved against the background of using a complex probiotic preparation in young poultry.