Influence of Artificial Light on Laying Hens Production of Heat, Moisture and Carbon Dioxide in a Floor Housing System

Investigations about laying hens reactions on artificial light conditions were carried out in a climate chamber equipped with a floor housing system for laying hens. The release of moisture increased during light periods probably due to increased activity which increased respiration rate but also on increased scratching which increased evaporation of moisture from bedding material. The daily average was 6.29 g henl h＂l at 4 lux and 5.97 g henl hl, at 93 lux which corresponds to a difference of 5%. The level of light intensity seemed to have little influence on the release of moisture. The total release of heat was slightly higher during light periods compared to dark periods. Explanations can be increased activity but also feed intake increasing the metabolic rate during light periods. The daily average of total heat production was 17.0 W per hen at 4 lux and 14.7 at 93 lux which corresponds to a difference of 16%. The release of carbon dioxide increased during light periods probably due to increased activity and respiration.