Chicken poop a lot and this attract flies in the summer not much you can do apart from clean out the coop every week at least but you will still get flies I'm afraid, you cannot keep the run spotless, chickens have to poop.
Haven't you got flies at the moment the bush flies are in Melbourne at the moment they are blown down to Victoria with the north winds from the grazing areas interstate north of us that have plenty of cow dung to breed in and then when they get to Victoria breed in farmland outside of the city's and move into the city shocking at the moment attacking my dogs ears and wave the flies off and ears dripping blood.and yes i clean up the yard twice daily.
So as stated you will have flies anyway but have to clean up the coop like the pigeon loft daily because the flies go for blood and you don't want them on chicken poop as well as you.
as to location down backyard not on a boundary and closer to your house than the neighbors also check on council regulations as to requirements of housing of chickens and setbacks from dwellings also limits of how many birds are kept ..
