Assessment of spatial variability of environmental variables of a typical house of laying hens in Colombia: Antioquia state case

This paper aimed to analyze the magnitude and spatial variability of environmental variables: Temperature and Relative Humidity Index (THI), Radiant Thermal Load (RTL), Globe Temperature and Relative Humidity Index (BGTH) and Enthalpy (H), inside a house for laying hens, in the state of Antioquia (Colombia) during the month of August. A traditional Colombian poultry house with natural ventilation was used. All variables were manually measured at equally spaced 1.0×1.0 m points, totaling 99 data collection points inside the poultry house. Geostatistical techniques were used through semivariogram analysis, and isochore maps were generated through data interpolation by kriging. The semivariogram was fitted by the restricted maximum likelihood method. The used mathematical model was the spherical one. After adjusting the semivariograms, the data were interpolated by ordinary kriging. The semivariograms and the isochore maps allowed identifying the non-uniformity of the spatial distribution of all evaluated variables throughout the poultry house. The results show that THI, RTL, BGTH and, H presented values above the comfort limits in the most significant part of the poultry house during the observed period. It is possible to concluded that the use of natural ventilation alone was not sufficient to guarantee the homeothermy conditions for the layers. Thus, it is suggested that in addition to natural ventilation, secondary modifications should be used to improve farm productivity.