Evaporative cooling of laying hens in Hawaii

A study was conducted to determine the effects of evaporative cooling on laying hens in a tropical environment of high relative humidity. Four strains of Single Comb White Leghorn pullets totaling 1,248 birds were housed in two identical enclosed houses except that in one the incoming air was passed through an air wash prior to entering the unit. The maximum temperature averaged 3.0 C lower and the relative humidity 15% higher in the unit cooled by evaporation. No significant differences were noted among any of the production parameters measured, although there was a numerical advantage for the evaporatively cooled unit in egg production, egg size, egg specific gravity, cracked eggs, and mortality. There were no consistent differences among the strains between the two units.