Well, I am happy to report that this year, unlike the last (the first winter I had them), my Russian tortoises are not trying to brumate, and are staying active and keeping up their appetite. Not entirely sure why that is, but I'm glad to see it. So, since one of them had some difficulty last time, I am overwintering them, and not sticking them in the fridge. I think I will continue to overwinter them until I can let them brumate naturally outdoors.