My Cornish are the only ones that did not great during winter. But it got like -30 for nights at a time and the male we lost was by himself so he didn't have any chance to huddle (yes, my birds huddle and share heat, but they have to here)That is related to the breed of the chicken, not where it is hatched. A leghorn, or other Mediterranean breed will be more heat tolerant than something like an Australorp. Being Mediterranean breeds they generally will also be more aggressive to the other birds.
That being said, I live in a cold winter climate and any heat hearty birds I've had did fine in the sub zero F temps. And the not heat hearty birds have been OK with the summer humid 90's we get.
I got my first 12 from Ideal, everything from heat hearty Anconas and Cubalayas to not heat hearty Black Australorps. They all did fine here.