How water system design affects the welfare of billions of chickens
Water is essential for all aspects of poultry physiology and welfare. Chickens are approximately 65% water; even short periods of water deprivation cause dehydration, distress, and rapid welfare deterioration. Yet water system design, maintenance, and management vary enormously across commercial poultry operations, with significant welfare consequences. This page reviews the evidence on how water access affects broiler, layer, and turkey welfare.
Two primary water systems are used in commercial poultry:
Nipple drinkers (closed system): Most common in broilers and layers. Provide clean water on demand. Welfare concerns: high water pressure causes beak tip trauma; low flow rates cause frustration; nipple height critical for access by small, weak, or lame birds.
Open drinkers (bell/plasson/trough): More natural drinking behavior; ducks and water birds strongly prefer open water. Welfare benefit: allow birds to submerge beak and nostrils during drinking (natural behavior). Management challenge: contamination and litter wetting.
During heat stress, water intake increases dramatically as birds attempt to cool themselves through evaporative cooling (panting). Water system flow rate becomes critical — if flow rates cannot keep up with demand during hot weather, birds experience combined heat and dehydration stress simultaneously. Heat-related mortality in broilers often involves a dehydration component even when water is technically available but inaccessible at needed volumes.
Ducks and geese have particularly strong water-bathing needs that extend beyond drinking. Immersion bathing is a behavioral necessity; without open water access, waterfowl show persistent frustration behaviors and feather and eye health deterioration. EU welfare guidance recognizes open water access as necessary for farmed ducks and geese, though enforcement varies by member state.