Yes, if you have those hogilo type hog houses, you do need to make sure they are really well secured. I think some tent pegs are longer than others and I would imagine several would be needed, unless the hog house is pushed under and being partially held down by, for example, branches from a bush. Even in areas where there are no foxes, dogs could also upturn them.
There have also been reports that some of those hog homes aren’t always very well built with loose wires, etc. which the hogs could get caught in or otherwise injured, so need to be carefully checked for any hazards.
But, if you can afford one, wooden boxes/houses are probably best and can also be cleaned out with boiling water to kill any parasite eggs which may end up there.