Hi, we've had GP's going on 5 years (we're on our second set) and originally we had a 'lid' on our cage because we thought our cats would bother the pigs. The cats never were interesting so we removed (and got rid of the lid). Recently, we got to young kittens and they like to think they're pigs as well. They get in the pig cage and sleep and sometimes play with the pigs. In the last few weeks, the kittens have started peeing in the pig bedding. Anyone have any insight of what I can do, aside from a lid, to keep the kitten from peeing in the pig cage?