Hi silverfox60017
It seems a bit unlikely that a female would be making a birthing nest already. It could have just decided to change nests during hibernation – they apparently do that. Having said that, if there are both males and females around they will mate, so it isn’t completely impossible as we seem to hear about more hogs choosing not to hibernate these days. In the past most have been youngsters not hibernating, but maybe that is changing.
In the normal course of events female hogs both start hibernation later than the males and return later than the males, so would likely not be back for a month or two. But human activity – for instance feeding and/or releasing hogs at different times from being, i.e. over-wintered, could potentially be impacting on the way hogs behave in the way of timings of various events.
If you have a camera focused on the hog house it would be interesting to know if the hog continues to be active or whether it might have continued with hibernation in your hog house. Let us know how things progress.