Abstract: A kit for converting a multi-stage egg incubator to a single stage egg incubator. The single-stage egg incubator conversion kit includes an air intake system, an exhaust/ventilation system, a heating source, a cooling source, an environmental control system, and humidity system all being capable of incorporation into an egg incubator. Components of the air intake system, exhaust/ventilation system, heating source, cooling source, and humidity system are operatively connected to the environmental control system to provide environmental control within a setter of the egg incubator, including selective cooling capacity, selective heating capacity, selective air flow between the setter internal environment and an external environment, and selective air flow from the external environment into two or more zones within the setter internal environment.