**1. Introduction**

Water is the most abundant and widely distributed chemical compound in the world [1]. Though water in the natural state is one of the purest compounds known, there is difficulty finding a freshwater source that has not been altered by man [2, 3]. The use of drinking water with high physical, chemical and microbiological qualities is vital in poultry production as one single water source serves several birds. Hence, any problem in water quality would affect a great number of birds [4–6]. Birds consume approximately 1.6–2.0 times as much water as feed on a weight basis [7]; therefore, any deviation in water quality could have more pronounced effect on poultry health and production than feed [7, 8].

Water is an essential nutrient in animal nutrition and plays roles in poultry metabolism including thermal homeostasis [9], food digestion and absorption, nutrients transport, and waste products elimination from the body [10]. It also makes up 70 to 80% of lean body mass by weight in birds [11–13].
