|I think she will have the kittens in the house she has been staying in at night and most of the day.
She needs to stay in all of the time now
that she is pregnant. She will just have to put a hold on her bird hunting activities because you cannot guarantee her safety or the safety of her kittens if she is outside (any time of the day or night).
ETA...If she goes into labor during the day while she is outside (very possible), she and the kittens will be in danger (especially because of the cold temperatures) and it is very likely you would not be able to find her nest. Again, I cannot stress the importance of this enough, she needs to be inside all of the time until she is done weaning her kittens and