Relation of diurnal temperature and humidity ranges to egg production and feed efficiency of New Hampshire hens

Abstract

The effect of environment on the production and size of eggs, feed efficiency and mortality of New Hampshire hens in individual cages was studied simultaneously in five areas of Guatemala having temperatures covering a range of 0°–45° C. with variable humidities.While birds housed in the tropical lowlands did show visible signs of thermo-stress, there were no significant differences in egg size, production, feed consumption, mortality and body weight between areas or between groups within areas. The inconsistency of these data with other published reports is explained on the basis of the observed extremely wide diurnal range for temperatures and humidities. An attempt is made to present accepted physiological phenomena in the form of a working hypothesis wherein the diurnal temperature range is related to the fowl's tolerance to thermo-stress.