If what Deborah says is right, then I guess the smaller prey is the reason why they haven't fasted! It makes sense.
I think being very sensitive to dropping ambient room temps really makes sense. It would reflect the experiences of both sides- that "they'll fast in fall/winter season" and "if you maintain their temperatures/husbandry, they won't fast" meaning at least some of the BP's that fast might be because the owners don't maintain level room temps throughout the year.
I'm curious too! Assuming you can keep the room temp exactly the same through the winter as it is the rest of the year.