Hi shinamae
I can sympathise! There is one cat here, who can get into just about anything. One of the best things I have found is a fairly large sheet of perspex balanced on earth filled flower pots. As low as a hog can fit under. I think it was 2 litre pots. Most cats don’t want to have to crawl on their bellies, but that one sometimes did.
But I also tried putting bricks in the tunnels of the hog houses to reduce the height. That was on the basis that maybe the cats could squeeze one way or the other but not both at once. That also worked, but the cat referred to wasn’t around then. The hogs managed to negotiate it without any problems.
But please don’t feed the hogs mealworms. They aren’t good for them due to a not good ratio of phosphorous and calcium and cause bone problems. So best avoided for hogs completely.
Perhaps your neighbour could be persuaded to keep the cats in at night. Night is a dangerous time for cats anyway. Although I suppose that would still leave the suet pellet problem!
Good luck, I hope you manage to solve the problem one way or the other.
p.s. you can put images on here if they are already elsewhere on the internet with a link. Or there is some information here in case you haven’t seen it: https://www.hedgehogstreet.org/photographing-hedgehogs/
