OH GOD, YES.
For the last 4 months of winter, the brats have been on and off their food and only recently is starting to take again. Had the same problem last winter but I'm smarter this time around--
I only offer food if they come to the front of the tank at night during the winter months (which is sometimes once every two weeks or so) so not only do I not waste rats but they're getting conditioned to come up to me if they're hungry.
(actually, it's probably the other way around--I'm all "hey, look I can make the pythons come to me by pretending I have food." and they're all like "hey, look I can make the human give me food just by coming up to the front of the tub.")