THE REALITIES ABOUT POULTRY The Modern Farm - The Realities About Poultry_Seco | Page 54

laying hens. These effects are somewhat reduced towards the equator, as the difference in the
daylight proportion of a day changes less and less.
This physiological effect on poultry is important in terms of maintaining egg production in
commercial flocks, and requires supplementary lighting programmes. Regular and reliable
electricity supply is required for such programmes, otherwise the effect can be made worse by
breaks in the light supplementation system. A slow but steady increase maximizes the rate of
production. However, lighting programmes producing an effective daylight proportion in excess
of 17 hours per day can have a worsening effect on egg production. A 24-hour security lighting
system can have such an effect on egg production.
Birds do best in situations where there is plenty of natural light that does not raise the
temperature of the house. Natural light is preferable unless regular, reliable and well-distributed
artificial light can be provided. It is recommended that the interior of the house be whitewashed
to reflect light. The intensity or brightness of the light is also important. Egg production will
decrease at light intensities lower than five lux (the “lux” is the metric unit of light intensity and
can be measured by a meter similar to that measuring light intake into a camera lens), although
meat chicken will keep growing optimally at light intensities as low as two lux (not bright enough
to read a newspaper). These intensities are measured at the eye-level of the bird, not near the
light source. Unless supplementary lighting is spaced uniformly, there may be areas in the
building insufficiently lit to allow optimum growth or egg production. Designs for layout assume
that the light bulbs or tubes will be kept clean, as dusty surfaces will reduce light output.
BIOSECURITY ON POULTRY FARMS
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