There are many entry points that may not be visible to the naked eye. If you hear something in your attic or suspect there is a wild animal nesting in your home, contact a local wildlife technician to access the situation. The longer you wait to address the situation, the more extensive the damage could be, which leads to a hefty price tag. Any damage would need to be replaced, and if you catch the critter early enough, there may be alternative options to repairs and cleanup.
Another important factor with not addressing an wild animal in your home could be dangerous to you and your family's health. Some critters carry extremely dangerous diseases. For instance, a bat's poop, also known as guano, can cause a condition called histoplasmosis, mold like fungus, that can be breathed in through ventilation, and if not treated can lead to a weakened immune system and be fatal.
Rule of thumb, don't let these critters live in your space, and call someone who has the knowledge and experience to handle and remove these nuisances.
All Around Animal Control
WILDLIFE REMOVAL & NUISANCE ANIMAL CONTROL SPECIALIST