While the birds likely would have weathered the cold, with temperatures hovering around -25 degrees in the recent cold snap, zoo officials were concerned for chicks in the 51-member flock who are still maturing, Malu Celli, zoo curator, told The Canadian Press.
"We just don't want to expose them to too much," Celli said. “It's not necessarily that it's too cold for them. I believe that physiologically, they can withstand colder weather than what we have here, but these are not wild birds."
King penguins are used to the cold, but tend to live in more milder climates than their Antarctic-dwelling relative, the emperor penguin, Celli said.
She said the zoo usually moves the penguins inside temporarily because of the cold once a year.
"It's kind of like you can bundle up your kid, but then there's a point you're going to say, 'I know you're good, but I'd rather you stay inside now,"' Celli said.