I would check your cctv, in case, if you can, as sometimes very small hoglets turn up at this time of year. Also to make sure it isn’t a cat or rat eating the food. All year, until recently, the cats have not been eating the hog food here – they usually just turn up their noses at it, but now one has decided it likes it. Very annoying as the hogs really need the food now and the current hog and hoglet visitors don’t seem keen on going into the box to eat – they prefer eating al fresco! The bowl of food in there has always hardly been touched in the morning, and I suspect that was by a wood mouse.
Re. the hog hibernating – Just my own thoughts, but I would be inclined to let him be. He will have made his own nest inside the dog kennel. Hogs have been making hibernacula for millions of years without our help and my feeling is that they are better at it than we could ever be. It isn’t always about keeping warm, as such, but maintaining the correct temperature, etc. Adding to it could alter the balance and even, potentially, cause it to partially collapse. I would leave him some extra hay/leaves nearby, so that if he wakes up he can make his own adjustments. Also, bear in mind that, apparently, they sometimes move nests during hibernation. So having some food near to hand and especially some water might be handy, although not everyone wants to keep putting food out all winter.
I’m beginning to wonder whether the mature female here is going to hibernate at all. She is already out and about a good 2 weeks later than she was last year – it is always a treat to see her, though.