Hi Dollydream
This is the Hedgehog Street information re. hog house cleaning: https://www.hedgehogstreet.org/cleaning-out-boxes/
So in theory, now is a good time to clean out the boxes. It may look clean, but there could be parasites or their eggs in there if the bedding has been there for a while. It’s possible the hogs are just using the house for naps between snacks, so there may not be one in there during the day, but I would explore gently first, in case there is. If there is, leave it be and try another day.
It does seem unlikely a hog would use a box with a dead hog in it, but I suppose it may depend on whether a dead hog had stopped smelling. Hogs are not known for always being predictable! But hopefully there won’t be another dead one in there this year.
Good luck, I hope you get a chance to clean out the hog house. Also that you continue to enjoy the visits of all the hogs. Happy hog watchcing!