Keep the feces directly under the roosts turned under each morning...what they can't reach, won't attract them. You could also start feeding fermented feeds, which leaves the fecal matter less attractive to flies as the feed is more completely digested and doesn't have any sugars in it to attract flies. I haven't seen a fly in my coop or in the yard on feces for three years now since feeding fermented feed. It's easy to do and don't cost a thing to ferment your feed.
That's just one reason to feed fermented feeds...there's a whole list of good benefits to it, not the least of which it will cut your feed bill nearly in half and your flock will enjoy a healthier life. Here's a link to any questions about it and this page will have a list of the noted benefits from feeding the FF.
http://tikktok.wordpress.com/2014/04/13/fermented-feed-faq/
That's just one reason to feed fermented feeds...there's a whole list of good benefits to it, not the least of which it will cut your feed bill nearly in half and your flock will enjoy a healthier life. Here's a link to any questions about it and this page will have a list of the noted benefits from feeding the FF.
http://tikktok.wordpress.com/2014/04/13/fermented-feed-faq/