No it's not normal. This is new behavior so something must be upsetting or stressing your cats out. Cats are very sensitive creatures and they can easily act out if something changes in their environment. Have there been any changes recently in the household like new people or pets, rearrangement of furniture or even a change in schedule? Any of these could be a factor in your cats behavior. Have you changed your habits in keeping the literbox clean or moved the literbox recently? Those are the most common reasons cats start going potty in undesirable locations. As for the chewing, it's harder to determine a cause. Do some research on cat behavior to help find a solution and take them to a vet to rule out any medical conditions and to get some expert advice.

yea. i've tried looking it up on the net and stuff--but i haven't found anything about the chewing. i know a lot of cats like to suck wool and stuff, but i've never seen anything like this. it's like she really just enjoys chewing. i'm afraid it'll hurt her teeth. nothing has changed, they have set feeding times, i change the litter the same time every week, we haven't had a lot of visitors-less than normal, even. they've both been to the vets recently. i don't have a clue what to do . . .