When starting chicks in the barn, bright light and good intensity are keys to success. During the first three days of the chicks’ life, at least 20 lux is recommended. Additionally, one hour of continuous darkness must be provided to the chicks by at least 24 hours from placement in each 24-hour period. From day five of placement a dark period of at least four continuous hours in each 24-hour period is required. Dark periods must be no more than 20% of the intensity of the light period.
Darkness benefits birds by allowing them to sleep and develop 24-hour day/night rhythms which is important in immune function, growth rate, digestion, lameness, and general health. Using a light meter can be helpful to monitor and adjust lighting as necessary.