I'd disagree with you Witton, whippets feel the cold more than most dogs, and not having the pups litter mates to huddle up to, she will be cold by her self and then she will cry all night,
a heat-lamp just for the night time through the winter is a must for whippet puppies living outside IMO, a hot water bottle is ok (I wouldn't without checking on it every hour or so), beacuse it must be wrapped in a blanket or towel to save the pup burning, and the pup must not be able to get to it and chew it, plus a few hours later and it becomes cold again,
heat lamp on a chain is much better,