Laying hens are housed in cages or in aviary system in one or more tiers. Droppings fall into a manure pit (deep pit) or a channel beneath the cages by themselves or with the aid of a scraper together with spilled water from the drinkers. The layer manure is removed once a year or less frequently by scraper or front loader on a tractor. In some systems, the ventilation system for the house is designed so that warm air is used to dry the wet manure in the deep pit or channel.
