My seventeen year old sister and her boyfriend live with my parents. There is animal feces and hair in every room and the house smells terrible. Who would I call to report it?

You should call the town Board of Health to file a complaint and insist it is an emergency and they must send out an inspector immediately because there are children living in the house. You have described a serious health risk. The health department will arrange an inspection and will give your parents, and the owner if they don't own the dwelling, an order to clean the premises. They may face eviction and court fines if they ignore the order. The authorities may also report them to the local child protective services agency. You can call CPS if you would prefer to be removed to foster care.