Alternative (non-cage) systems
These systems, which include those that fall into the category of the EU-Directive “Alternative systems”, are operated from inside and the keepers enter them. All current alternative systems provide the birds with nest boxes and litter as well as perforated platforms. Elevated perches may or may not be included.
Indoor
Indoor systems may, or may not, be combined with outdoor facilities.
Single level systems contain all alternative systems where the ground floor area is fully or partially covered with litter and/or perforated floors in any combination. Birds have no access under the perforated floors. There is only one level for the birds at any one point, even if this level is stepped. (See figure 3.8).
Aviaries (Multi-level systems ) consist of the 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 are at least two levels available for birds.
There are many differences in layout. Three major categories can be distinguished.
- Aviaries with non-integrated nest boxes: aviaries with several levels of perforated floors with manure belts under them and separately arranged nest boxes (see figure 3.9) Feeders and drinkers are distributed in such a way that they provide equal access for all hens.
- Aviaries with integrated nest boxes: aviaries as above but where nest boxes are integrated within the blocks of perforated floors (see figure 3.10).
- Portal aviaries: aviaries with elevated perforated floors, the top tier of which is a single level which links the lower stepped platforms. The keeper can walk under and upon the top tier. Nest boxes are integrated in the system (see figure 3.11). Typically the litter goes fully under all the platforms, providing 100% littered ground floor.
Outdoor
In combination with the above mentioned alternative systems some additional area is provided. This can be either one or both of the following possibilities:
- Covered verandas : a covered area outside, but connected to the hen house, is provided and can be available during daylight hours. This area has a concrete, or other suitable floor, usually covered with litter. The climate is similar to that outside except for rain (because of protecting devices). In some countries this area is referred to as a Wintergarten.
- Free-range : an outside uncovered area is provided, mainly covered with vegetation. Hens have access from fixed or mobile houses to this area via popholes in the wall of the henhouse and in the covered veranda, if present. Several pens may be used in rotation, or mobile houses may be moved, to control parasites and maintain good pasture quality. Areas near to the house may be covered with free draining material to maintain good hygiene both outside and within the house.
Others
Several systems do not fit into the previous categories, because they are obsolete or rarely used nowadays, e.g.:
- Litter-less or fully littered floor systems: obsolete as they do not meet the requirements of the EU-Directive (e.g. "perches must not be mounted above the litter").
- Tents: rarely used, but maybe suitable for certain situations.
- Percheries: obsolete as they do not appear to meet the requirements of the EU-Directive (e.g. "the levels must be so arranged as to prevent droppings from falling on the levels below").