At that temperature, I would say they can handle direct wind too. Heck, if i had to put my chickens away at that temperature, they would be out about ten days all year. That's t-shirt weather, pushing towards shorts as well! Silkies are pretty cold-hardy for their size. I have one to help keep my teeny little Seramas warm, but if I had three I wouldn't worry about them until below freezing, for sure.