32 LOHMANN TIERZUCHT › MANAGEMENT GUIDE 32 Light Sources Different kinds of light sources such as incan- descent lamps, tubular fluorescents, energy- saving lamps and most recently LED lights are used in poultry facilities. Incandescent lamps are banned already in many countries since they cannot convert electric power to light efficiently. Therefore, light sources such as LED-lights which are more energy- efficient and long-lasting are chosen more often in modern poultry houses. Regardless of advantages and disadvantages of each light source some, important basic facts must be taken into consideration, while choosing them for poultry. › › The frequency of the emitted light should be at least around 150 Hz to avoid flicker- ing. › › It is advisable to use Poultry-specific light sources. They're expensive but gener- ally adjusted to poultry vision in terms of light spectrum etc. In general light sources which approximate the natural spectrum are recommendable specially for produc- tion period. › › The light intensity could be seen much higher by poultry than human being de- pending on light source. Therefore, the conventional Lux meters which are de- signed for human vision, have limitations to measure the correct light intensity for birds. For example, they cannot detect the UV-A light. › › For measuring the correct intensity of LED-Light, a specific Lux-Meter for LEDs is required. › › The light color alone measured in Kelvin seems to be insufficient for the valuation of the light spectrum of light sources, be- cause it only reflects the wave length and not the whole spectrum including UV-A light. Anyhow aside from light spectrum, at least light source with warm-white colors between 2700–3000 Kelvin should be considered for poultry houses. › › Light sources for birds should designed to be dimmable. Not all light bulbs have the ability to be dimmed or dimming could cause flickering or shorter lifespan. › › Direct and uneven light and shadows should be always avoided. While using LED-lights diffusers can be useful to avoid direct light. › › To avoid stress after transfer of the pullets to layer house, it is important to adapt al- ready pullets to natural daylight if they will be kept in open house facilities. › › Light sources should be designed for cleaning and disinfection processes in a poultry house.