Glossary:Poultry housing
Poultry housing can be divided into:
- battery cages
- straw beds
- aviaries
- free range
Battery cages are animal housing systems where the laying hens are kept in cages, one or more in each, inside closed buildings with forced ventilation and with or without a lighting system. Birds are kept in tiered cages, usually made of steel wire, arranged in long rows. Droppings fall through the bottom of the cages and are collected and stored underneath in a deep pit or channel or are removed by a belt or scraper system. The droppings from laying hens in battery systems are not mixed with other material such as litter and may be dried or have water added to make the manure easier to manage. There are three common battery systems for laying hens in use in Europe:
- with manure belt: battery cages where the manure is removed mechanically by a belt below the cages to outside the building to form solid dung/farmyard manure. Movable belts, e.g. made of “non –stick” polypropylene, below the cages on which droppings are collected and are transported outside the house to a closed storage. In improved systems, there is provision to dry the manure on the belts by forced air through perforated pipes or drying tunnels over the cages. Battery cages with manure removal by scrapers are also included here;
- with deep pit: battery cages where the manure falls into a deep pit beneath cages where it forms slurry. The birds are housed in cages 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 of 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 a channel;
- with stilt house: battery cages where the manure falls on the floor below the cages where it forms solid dung/farmyard manure and is mechanically removed regularly. This is similar to a deep pit house except that there is a variable valve between the cage and dropping storage areas and large openings in the dropping store walls that allow wind to pass through and assist drying. Cage and dropping areas of the building are separated so droppings can be removed at any convenient time without disturbing the birds.
Laying hen housing on straw-beds (deep litter-loose housing) are animal houses where the floor is covered with a thick layer of litter (straw, peat, sawdust, or other similar material binding the manure) that is removed only at intervals that may be several months apart. A simple closed building that is thermally insulated and with forced ventilation or natural ventilation. At least a third of the floor area must be covered with bedding (e.g. chopped straw, wood shavings) and two thirds arranged as a pit covered with slats to collect droppings (waste voided by poultry) over the 13 – 15 month egg laying period. Laying nests, feeders and water supply are placed over the slatted area to keep the litter dry. Corresponds to management systems of poultry manure with litter (IPCC, 2006).
Aviary housing (also called multi-level systems or percheries) consists of a ground floor plus one or more levels of perforated platforms, from which manure cannot fall on birds below. At some point across the system there will be at least two levels available for birds. An aviary house is a construction with thermal insulation, forced ventilation and either natural or artificial light. They can be combined with free range and outside scratching area. Birds are kept in large groups and are free to move over the entire house area over multiple levels. The space is subdivided into different areas: feeding and drinking, sleeping and resting, scratching, egg laying. Because animals can use several levels, higher stock densities are allowed in comparison to the deep litter regime. Droppings are removed by manure belts or collected in a manure pit. Corresponds to management systems of poultry manure without litter (IPCC, 2006). For the purposes of IFS, aviaries with deep little should be classified as deep litter housing. Aviaries where the animals have access to outdoor areas can be classified as free range.
Free ranges (outdoors) can be covered with grass. The birds have access to this area from houses via popholes in the wall and from the covered veranda, if present. They will use the area if they feel there is sufficient shelter. The shelter may be trees or bushes, but it can also be artificial shelter (elevated nets, tents, mobile hen houses). Also, a fence can be used as cover to walk along. Providing a sand bath is another way to attract poultry to use these facilities. Areas near the house may be covered with free-draining material, in order to maintain good hygiene both outside and inside the house.