Figure 1 illustrates a fairly typical water consumption pattern for a 40' X 500' broiler breeder house with approximately 10,000 birds. When the lights are off at night the birds drink little if any water. When the birds are fed first thing in the morning there is a peak in water consumption that lasts a couple of hours. Water consumption plateaus for the remainder of the afternoon then slowly drops off as the birds gradually stop drinking water in anticipation of the lights shutting off at 10:3...0 pm (11:30 DST). Figure 2 illustrates a not so typical pattern. There is the usual peak in water consumption in the morning, but then there are two additional periods of very high water consumption during the afternoon. These periods of high water consumption are the birds’ response to a heat stress situation.