Marcia, all my teeny hogs and sick hogs needing treatment are initially given fleece blankets as bedding, hence no hay and dust particles. Once these particular hogs have grown/recovered, they can all be seen sporting the latest hay and dust particle embellishments!
Hibernation factors appear to be more complex than merely initiated by weather conditions + lack of natural food. An individual readiness appears to be a factor too...
Some hedgehogs purportedly don’t hibernate at all in the UK, yet some hogs kept indoors by carers, do!
With the exception of the very poorly hogs, every hog I’ve ever had in my care over winter (in a constant warm environment and with plenty of food available at all times) has hibernated at some point, even if just for a few days/weeks. Even siblings housed together have gone into hibernation, one at a time, over the course of a few weeks - goodness knows how the first hibernators aren't disturbed while the others are still awake and creating merry mayhem!
