Got this info from another thread (feather and mountain man):
Banana Boat sunscrean works well. (APPLY TO COMBS AND RUB IN UNDER FEATHERS AVOID EYES BUT GETS ALL EXPOSED SKIN)
Plus vanilla either extract 1/2 water 1/2 mixture (YOU HAVE TO DRENCH THE CHICKENS FOR IT TO WORK) several times a day
or a vanilla perfume that I buy and the Dollar Generall store works well too. (DO NOT SPRAY IN EYES JUST FEATHERS) twice a day
You can also dust the chickens with a mixture of half baby powder and half seven dust
As an outdoor reppellant for living areas vanilla sented candles burning around your area works well too
Just wanted to share. The gnats are getting worse here but we are still fighting back.