Producers who decide to build a hoop structure need to treat the construction project as they would any project involving a new structure. Aspects to consider include site selection; proper access to move feed, bedding, and pigs; usefulness within an existing operation; proximity to neighbors; availability of services and utilities; and the possibility of using the structure in conjunction with existing buildings. Provide at least 10 feet of space between multiple hoop structures to allow space for tractors to travel between buildings, snow removal, and drainage.
Hoop structures are naturally ventilated and should be sited to take advantage of the summer prevailing winds. For much of the midwest, the structure is oriented in a north-south direction to take advantage of the prevailing summer winds. Prevailing summer winds should blow into the south end of the building where the feeders and waterers are located and exit on the north.
In a grow-finish hoop structure, a 15- to 25-foot long concrete pad, or approximately 1/4 to 1/3 the length of the structure, is provided for feeders and waterers. This pad should extend the entire width of the structure. In such a location, the pad is sloped 1% to 2% (1/8-inch to 1/4-inch drop per foot of length) to the south, or away from the bedded area. The runoff must be stored and field applied.
A typical hoop structure is 30x72 ft and holds approximately 180 head of finishing pigs in one large group. Figure 3 shows a common layout for a grow-finish hoop structure. Stocking density usually is about 12 square feet per pig. Table 2 shows the typical space distribution in a hoop structure used for housing grow-finish pigs.
Figure 3: Common layout of a grow-finish hoop structure. Source: Based on Figure 3, Hoop Structures for Grow-Finish Swine, AED41.
Table 2: Space distribution in a hoop structure used for grow-finish housing. Note: In hot weather, additional waters may be added. Source: Table 1, Hoop Structures for Grow-Finish Swine, AED-41.
Livestock panels or gates form the endwalls at animal level. To reduce drafts in the winter, these gates can be covered with tarps, sheets of galvanized steel, recycled plastic, or plywood. The bedded end endwalls are closed to reduce winter winds using commercially available tarps or plywood sheets. Many producers close the north end in cold weather, especially in northern climates of the United States. Some producers may close both ends in cold weather; however, closing the structure too tightly can cause more of a problem than leaving it open. In the summer, both ends are totally open, with the steel, plastic, or plywood panels removed from the end gating to increase airflow in the pig zone.