Guidelines for growing period
Start pullets with 20 to 22 hours of continuous and bright (30 to 50 lux, 3 to 5 foot-candles) light during the first week of age. Alternatively, an intermittent lighting program (4 hours of light followed by 2 hours of darkness) can be used during the first week of age. The dark period (or periods) serves as 'resting time' and helps strong chicks show the weak chicks how to find feed and water.
The light intensity should be 30 lux (3 foot-candles) during the first week of age, after which it can be reduced to 5 to 10 lux (0.5 to 1.0 foot-candles) in cages or to 15 lux (1.5 foot-candles) when grown on the floor. The higher light intensity for floor-grown birds will allow the birds enough light to navigate their environment. In cages, there should be 10 lux (1.0 foot-candles) at the feeder and 5 lux (0.5 foot-candles) inside the cage.
Reduce the day length weekly to reach 9 to 10 hours at 10 weeks of age or, if longer, the day length dictated by greatest natural day length in open or brown-out houses. In Hy-Line Brown and CV-22 varieties, a constant day length of 9 hours may be used to control excessive body weight after 10 weeks of age.
The light intensity in the grow and lay houses should be similar because pullets can be stimulated to start egg production by an increase in light intensity, even if the day length is unchanged. Therefore, the light intensity in the grow house should be gradually increased in increments of 5 lux (0.5 foot-candles) per week to the intensity used in the lay house, starting 2 to 3 weeks before the pullets are moved.