Stalls have many edges and corners. These, together with large amounts of urine- and faeces-soaked bedding, provide an ideal fly breeding habitat.
Cleaning with hand tools is time-consuming and difficult to accomplish completely.
Water and feed (grain and hay) must be provided in the stalls or in free choice sheds. Feed and water spillage contributes to fly breeding in the bedding.
Each horse produces about 14–16kg of manure per day, which provides additional opportunities for fly breeding.
Frequent removal of contaminated bedding in horse stables presents a disposal problem. If the manure is piled, the piles can support large amounts of fly breeding (unless the piles are compacted and covered with plastic sheeting).
The problems of manure removal and disposal by hand for sheep and goats are similar to those for horses, although cleaning is much less frequent.
Sheep and goats spend more time sleeping and eating in open shed shelters than horses. They therefore create more of a problem with flies breeding in manure- and urine-contaminated bedding.