Great, I got long, complicated answers (as in - too much for this brain to remember and type out accurately) to both questions, so will email them to you once I get them.

Traci, the vets said the reaction to the wet food sounds like a food allergy, and nothing to do with whether the food is wet or dry ... again, a long answer, but I'll email you the file.

As for the chewing of cardboard, they talked about it maybe being a soothing thing to do, like some people chew gum ... you'll hear it!