Winter housing for swine welfare

Many specialty market or private use pig producers opt for housing swine in barns at least part of the year, often during the winter. Providing housing to swine in cold winter weather includes the decision as to whether to modify the barn environment to keep it warm or to let the indoor temperature be similar to outside conditions.

The distinction between these facilities is observed during cold winter weather, when farm animals (especially pigs) need the most protection. This article outlines issues that help in decision making for pig welfare and economics related to warm and cold housing. It should be noted that commercial pork producers typically house the animals year-round in climate-controlled facilities.

Cold housing
Cold housing is a barn environment that is left to its own devices to be the same temperature as outdoors; so cold in the winter. It will essentially be the same temperature as outside conditions, while providing protection to enclosed animals from the worst of winter weather winds and precipitation.

Warm housing
Warm housing, also known as "modified environment" or "climate controlled," needs to have additional heat supplied in order to remain above cold outdoor conditions. The heat is referred to as "supplemental" heat since it is supplied to supplement heat already produced by pig body heat within the housing unit or barn. Supplemental heat is typically from electricity or fossil fuel sources via space heaters or radiant heat units.

Temperature needs varies for young and mature pigs
Swine have a very narrow thermo-neutral zone; you could call this a comfortable temperature range for pigs.

Mature pigs can handle cooler temperatures than immature and growing pigs; however, once those temperatures fall below 40°F for adult swine, the ability to add further protection from the cold is a must. Mature swine can adapt to winter temperatures, however this is commonly at the expense of body condition, see Principles of body condition scoring in swine.

Growing pigs (birth to about 6 months), however, do not yet have the physical capacity to adequately withstand temperatures much below 50°F. Warm housing, with heat from a sow and/or supplemental heat source, is necessary for animal welfare and growth efficiency of pigs smaller than 200 lbs.

Suggested temperatures are found in Table 1. But there may be reasons beyond what the animals can tolerate to prefer warm housing versus cold. More on that a bit later. Knowing the thermo-neutral zone that is appropriate for the pigs you are growing will aid housing decisions.