Air velocity alters broiler performance under harsh environmental conditions.

The effect of air velocity (AV) on weight gain, feed intake, and feed efficiency was studied in male broiler chickens exposed to a constant 35 C, 60% RH, and continuous illumination from 4 through 7 wk of age. In two separate trials, AV of 0.5, 1.5, 2.0, and 3.0 m/s (Trial 1) and 1.0, 1.5, 2.0, and 2.5 m/s (Trial 2) were used. The fifth week was used for acclimation to the targeted environmental conditions. Weight gain was significantly higher in broilers exposed to AV of 1.5 and 2.0 m/s in both trials, which coincided with significantly higher feed intake and feed efficiency. Exposure to the low AV (0.5 and 1.0 m/s) resulted in weight gain, feed intake, and feed efficiency that were less than those of broilers exposed to high AV (2.5 and 3.0 m/s). In all treatments, broilers developed hyperthermia, but there were no significant differences in body temperature (Tb) among the birds. It can be concluded that AV has a significant effect on broiler performance; the optimal AV was found to be 1.5 to 2.0 m/s.