Yes, hogs can squeeze through surprisingly small holes! I hope the hog who got in was none the worse for the experience. I also hope the 20ft run is still working. I have found that some rats seem nervous of, i.e. ‘furniture’ being moved around, but others are bolder. So frustrating when the hogs are needing food in the run up to hibernation. But, just be aware that hogs are much better climbers than they are often given credit for.
Perhaps the cats need a good talking to that they are supposed to keep the rats away completely!