Method of incubating poultry eggs in an incubator comprising one or more incubator sections wherein an air flow is generated within each incubator section and the CO2 content and/or the air humidity are measured in air horaogenized by the air flow. Fresh air is supplied to adjust the measured air humidity to a set point value provided that the measured CO2 content is below a predefined upper limit. The fresh air is mixed into air already present in the incubator before the mixed air is guided along the eggs. Incubator with air inlets comprising a control unit responsive to sensors for measuring the air humidity and the COa content of the homogenized mixed air in the incubator.
