Kenny Coogan explains the countercurrent adaptation that keeps birds’ feet from freezing in ice cold water, standing on the ice and even standing in very hot water without damage.
Source: Backyard Poultry, October 26, 2021. Link. Countercurrent heat exchange systems enable many species of birds to keep their feet submerged in icy cold water or the ability to stand on ice for hours without the consequences of frostbite.