Abstract: A method of improving egg production in poultry by irradiating poultry with energy levels, the first one of which is within a wavelength band of 600 to 670 nanometers and is delivered at a rate of at least 10.sup.13 quanta/second/cm.sup.2, and, in the case where this first radiation is less than 10.sup.13 quanta/second/cm.sup.2, at least 75% of the total delivered energy is within the first wavelength band. The second radiation energy level is within a wavelength band of 400 to 600 nanometers and is delivered at a rate of at least 10.sup.14 quanta/second/cm.sup.2, and, in the case where this second radiation is less than 10.sup.14 quanta/second/cm.sup.2, at least 80% of the total delivered energy is within the wavelength band of 400-600 nanometers. The invention also includes a control of the time during which the irradiation is delivered.