What do I need to use for controlling flies

[bama fan]

I have my bobwhites in a barn with plenty of ventalation but have a nice collection of flies too is there any type of spray or dust I can use that want hurt my birds

 

[ChickenToes]

I use DE and a fly trap.

 

[Wifezilla]

Fly traps work but DAAAAMMMMMMMNNNN they stink!! Any brand that doesn't smell so bad to people??