The pre-incubation treatment of eggs of the Ross 308 cross-country with a composition consisting of colamine, succinic acid, serine and vitamin B6 had a positive effect on the incubation biocontrol parameters, antioxidant status and histogenesis of some internal organs of the poultry gastrointestinal tract. Thus, the output of chickens in the experimental batch exceeded the control by 2.47%, and the hatchability by 2.23%. The thermogenesis of chickens from the experimental group was also better; the temperature was significantly higher by 0.7-1.3 ° C (p <0.05, p <0.01) as compared with the control. The antioxidant properties of this composition contributed to a decrease in the ORH level by 2.5 times (p <0.05), (MDA) - by 1.3 times (p <0.05), with an increase in the peroxidase activity by 17.65%, SOD- 1.6 times (p <0.01), respectively, relative to the control. internal organs for histological examination were taken. The decrease in the anomalous intensity of free-radical reactions and, as a result of lipoperoxidation, had a positive effect on the histoarchitecture of the muscular and glandular stomachs. Thus, a tendency to an increase in the thickness of the mucous membrane of the muscular stomach by 16.6% was recorded, as well as its cuticle significantly 1.4 times (p <0.05), glandular - 1.2 times (p <0.01) relative to control. These data allow us to conclude that the study of the histological characteristics of the stomachs in chickens at the age of day is an important marker of their future adaptive capacity in postembryogenesis. The literature suggests that increasing the thickness of the glandular mucosa will contribute to better digestion of feed, the viability of intramural regulatory processes, intestinal microbiocenosis and other functions of the digestive system as a whole.