I have a sand base run with DE and PDZ mixed into the soil. I rake the run and coop everyother day. i keep geese and chicken together in the run and free range during the day. I have a bizillion flies and they are all over the food dishes. The grese have a small bucket of water for dunking and when I picked it up tonight there were maggots under it!! How do I kill them and what have I done wrong?? This is my first attempt at chickens and I am very discouraged.