Cable installers have put TV cables through the ventilator screen without securing it to prevent rat access.  This access allows a nice warm place for the rats to sleep.  The rats can go out during the night time and gather snails, slugs or dog feces for food and then return to their nice snug nest in the fiberglass insulation.  They bore tunnels up into the insulation and get between the floor and the insulation.  They sleep there during the day so the home owner is unlikely to see them.  If you have a problem that has happened like this see if the cable installer will come back and correct the problem otherwise call us at 457-4341 or 1-800-828-5508.  We will correct the problem, install traps to catch the critters that are left inside and we will install bait boxes outside with traps in them to help eliminate the problem.