[Treauremapper]

My idea would be to install a dog kennel around the hutch. One of those chain link wire kennels with a door, so that the kennel sits in the center. The entire structure would need to have a roof or be in a porch with a roof. If it is strong enough to prevent dogs from getting out, it should be strong enough to prevent a cat from getting in.

But, sadly, sometimes it is better to rehome a guinea pig.