In many ways we are still where we were 50 years ago in layer lighting. Reports in the literature prior to 1920 showed the need for long day length 14 hours of day length with natural daylight in most cases extended by kerosene or gas lanterns. While the lanterns are gone, we still follow for our most traditional layer lighting programs somewhere around a 14-hour day length.
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Department of Animal Science, Agricultural Experiment Station, South Dakota State University
Hamre, Melvin L., "New Concepts in Lighting Layers" (1978). South Dakota Poultry Field Day Proceedings and Research Reports, 1978. 10.