Poultry Lighting Program Calculator

Each phase serves a different biological goal, and intensity follows it. Brooding uses relatively bright light (around 30-40 lux) so day-old chicks can find feed and water quickly. Growing drops to dim light (as low as 5 lux) specifically to discourage early sexual maturity. Pre-Lay ramps intensity back up alongside hours to stimulate reproductive development, and Production settles at a mid-range level that supports consistent laying behavior without triggering feather-pecking associated with overly bright, prolonged light.

No -- it's by design. This calculator steps light hours down from about 11.5 toward a floor of 8 as birds approach 10 weeks of age, and a flat or shortening photoperiod during rearing is exactly what delays sexual maturity. What should never happen in Growing is the opposite: increasing light hours mid-phase, since a lengthening day length is the hormonal cue that can trigger early sexual maturity and undercut the frame-development goal of this phase. The caution runs the other direction in Production, where light hours are fixed at 16 and should never be decreased, since cutting day length mid-lay can trigger a molt or a drop in lay rate.

They sit at opposite ends of the program. Brooding runs 20-23 hours of light at higher intensity to maximize early feed and water access for chicks with no light-hour concerns. Production runs a fixed 16-hour day at moderate intensity -- enough to sustain lay rate consistently, but well short of Brooding's near-continuous schedule, since adult hens no longer need constant light exposure.

Age is what phases are built around, but this calculator's Production Phase selection -- not raw age alone -- is what actually drives the light hours and intensity output. Within the Brooding, Growing, and Pre-Lay phases, age further refines the step-down or step-up schedule (for example, how many pre-lay weeks have elapsed determines how far light hours have climbed toward the 13-14 hour target, and how close a Growing-phase bird is to 10 weeks determines how far hours have tapered toward the 8-hour floor), but selecting the correct phase is the primary input.