REGIONAL DIFFERENCES OF SURFACE TEMPERATURE OF NAKED NECK LAYING HENS IN SEMIARID ENVIRONMENT

This study aimed to evaluate the regional variation of the surface temperature of naked neck hens in semi-arid environment using infrared thermography. The surface temperature was measured (776 observations) in four body regions (face, neck, legs and body) of 60 laying hens Label Rouge (naked neck). Were Measured environmental variables in the center of the shed: black globe temperature (TG), air temperature (TA), wind speed (U) and relative humidity (RH). TA was divided into three classes: Class 1 (24.0°C to 26°C), Class 2 (26.1°C to 28.9°C) and Class 3 (29.0°C to 31.0°C). Analysis of variance was performed by the least squares method and comparison of means by Tukey-Kramer test (p<0.05). Results showed significant effect of class TA, body region and the interaction between these two effects on surface temperature. There was no statistical difference between the TA classes for the face and neck. Legs and body presented difference between the TA classes. Averages between the body regions in the same TA class, there was statistical difference among all regions in the three TA classes. The neck presented the highest average in all TA classes studied, followed by the face and legs. The body presented the lowest average in the differents TA classes. It is concluded from this study that there are regional differences in the surface temperature of naked neck hens, where the legs act as thermal windows. Laying hens Label Rouge have advantage compared to other birds, since they have a greater surface area without feathers, facilitating heat dissipation.