I am looking for ways to help mange cluster flies. The previous owners used to treat the yard but since we have been here 3 years we haven't done anything. This fall the cluster flies were so bad. We would kill about 30 a day in the house and it would look like a scary Halloween movie on the backside of my home with the flies covering it. We have no idea how they get in the house. My girls are free range but really need to do something about the flies in spring/summer. Help!