Wherever there is manure, there are parasite larvae. The life cycle of all horse parasites involves leaving the horse host via the manure and then reinfesting a new host. Parasite larvae can do great internal damage to a horse as they migrate through the tissues. When a horse eats from manure-contaminated ground, he ingests parasite eggs. Along with deworming horses every two months to decrease the number and viability of the parasite eggs that are shed, the daily removal and proper management of manure is the best way to break the parasite life cycle.
Stable flies breed in decaying organic matter.
Moist manure is perfect breeding medium for flies. The life cycle of stable flies is 21 to 25 days from egg to adult. A female often lays twenty batches of eggs during her thirty day life span. Each batch contains between 40-80 eggs. When the eggs hatch, the adult flies emerge ready to breed.