Clearly, Prudie is not into the concept of rats as pets. I suspect she'll see lots and lots of mail about this.
If the conditions really are filthy, and dangerous to the animals, they should be reported to the authorities. However, it might be, from the description given, simply a smelly litterbox, and one of the cats having an accident.
If the living situation is as dire as it sounds - two people and eight animals living in a single room - her workmate has some serious problems. However, it sounds like the writer was already a little ticked off ("I only agreed to do it because of guilt,") and might be overstating things out of her annoyance.