Manure accumulated under the slats in breeder houses and under the cages in commercial egg houses provides an ideal habitat for fly breeding.
Leakage from waterers and poor drainage help keep manure moist and suitable for fly breeding.
It is often difficult or impossible to achieve sufficient airflow over the manure in the houses to dry it.
Poultry production is increasing and production units are becoming larger.
Laying hens excrete about 5% of their body weight per day. Even with the best manure handling procedures, this presents an enormous potential for fly development.
Frequent flushing and scraping, and disposal of the manure into a lagoon, similar to the systems used for some dairy and pig operations, is effective provided lagoon design and maintenance is satisfactory.
Often, however, flushing or scraping is incomplete and pockets of manure are left for fly breeding in the houses. If lagoons are overloaded, floating mats of solid matter, which support fly breeding, will occur.
In housing systems where the manure is allowed to accumulate for long periods, inadequate manure drying is common. Consequently, fly breeding is frequently a problem.
When accumulated manure is removed from houses, disposal often becomes a problem.
Manure is seldom stored in piles, due to the odors and fly breeding.
Distribution of manure on cropland and pastures in a thin layer will not support fly breeding. However, improper spreading, leaving deep clumps, can result in some fly production in those fields.
There is often insufficient land on which manure can be spread, due to the small acreage of many poultry farms and the limits to the amount of manure that can be used on cropland within a given period of time.
