how do you control them?? They can kill a chicken within a few hours around here (from what the farmers have said!)...they are terrible and just hang around your eyes and nose/mouth... my girls are shaking their face every few seconds...they have even retreated to their coop...even though its too hot to be in there the whole day... I cannot (meaning dont have ability) get a fan out there to have breezes to keep them away... any ideas??