Some may suggest you take it in. The problem with that is are you going to be around when she has them, and how much trouble will you have getting them readjusted to the cold when they get older? My rabbits are in a shed. It is not heated, but I don't have to worry about wind. One of my does had babies last night (it was -18C). They were fine, but I used heaters under the nest (see "The Nestbox" thread under "Rabbit Ramblings" for a cheap easy way to make heaters and how to use them) These might be dangerous outside, and they wouldn't work where wind would carry the heat away.