You're going to laugh ... but I was told that the insulation once was (but no longer is) made using soybean byproducts .... which served as a rat magnet. Supposedly the new stuff is not nearly as tempting a dish.

(And I won't quibble over whether that's a rat, mouse, or vole in the picture!)

What's needed is a 'Critter Abatement Technician,' or, perhaps, a 'FEline Replacement Rodent Eliminating Technician.' Good luck.