The article discusses issues related to the impact ofvariable incubation temperature (37.8°C-from the 1 st to the 14 th day; 39.5°C, two hours daily, in the 15 th -17 th days; 37.5°C - 18 th day; 37.0°C - 19 th -21 st day; relative humidity is 57.0%) on the growth and metabolic rates of the Hysex Brown and Lohmann Brown crosses chicken embryos as well as on the development of their visceral organs and the incubation effectiveness itself. Currently, most of the research is devoted to studying the influence of variable egg incubation temperatures while using one cross of chickens and comparison with the standard incubation mode. A necessary condition for the balanced development of productive bird embryos is the acquisition of knowledge about their morphophysiological parameters and metabolic needs, based on which it is possible to adjust regimes of artificial egg incubation. The research results have shown that the developed and tested incubation regime with variable temperatures is most effective for hen eggs of the Lohmann Brown cross compared to the Hysex Brown cross. This positive effect was expressed in a more intensive growth of chicken embryos and the development of some visceral organs (gizzard stomach, spleen), as well as in the most pronounced rate of gas exchange (CO 2 ), the highest energy value of embryos and the lowest total energy consumption for growth and metabolism in the period from 4 days of incubation to the hatching time. Differentiation of the temperature regime during embryogenesis has a positive effect on incubation results. The percentage of withdrawal of the Lohmann Brown cross young chickens is 4% higher than that of the Hysex Brown cross due to decreased embryonic mortality and decreased number of frozen embryos and suffocated chickens. This kind of research, in our opinion, is an auspicious one, and it is necessary to adjust the existing incubation regimes of hen eggs in various production areas.