Roosters prefer cool drinking water in both summer and winter

There is evidence that drinking cool water at high temperatures and warm water at low air temperatures may alleviate thermoregulatory stress and improve performance in chickens. We predicted, therefore, that when given a choice, roosters would choose cool over warm water in summer and warm over cool water in winter. We offered broiler breeder roosters tap water at 25°C and cool water at 8°C in summer and tap water at 12°C and warm water at 30°C in winter. Water was offered at 08:00 hr and 14:00 hr, each time for 45 min. There was no difference in water temperature preference during the first 2 days and the morning of the 3rd day in either season. Selection of a water temperature was made in the afternoon of the 3rd day, when cool water comprised 93% of the intake in summer and 86% in winter. Thereafter, om a daily basis, cool water intake ranged between 71 and 89% in summer and between 85 and 95% in winter. There was no difference in the proportion of cool vs. warm water intake between morning and afternoon. In summer, the total volume of water drunk in the morning did not differ from that in the afternoon, but in winter the roosters drank more in the afternoon than in the morning.