There is growing demand in Iowa for pigs raised outdoors or in deep-bedded systems without the use of antibiotics, growth promotants, or animal by-products. Currently many producers selling naturally-raised pork market their animals to a company that requires adherence to the Animal Welfare Institute’s (AWI) Animal Welfare Standards. One of the key components of these standards is the requirement for bedding and the prohibition of farrowing crates. While a pasture farrowing system is effective during most of the spring, summer, and fall, an alternative system is needed in order to farrow pigs in the winter for the naturally-raised pork market.

There are a variety of farrowing systems currently being used during cold weather to farrow pigs for the natural pork market. In general, all rely upon a primary heat source capable of maintaining a room temperature of at least 50º F and auxiliary heat sources (heat lamps, bedding pack, confined space) to create a warmer microclimate for the young pigs. The use of adequate bedding and a design in harmony with the natural instincts of the hogs are key to the success of the example systems. A final critical consideration is a breeding program that insures sows in a particular room farrow within a short time frame (7 days or less).

Three unique systems, detailed in this report are free stalls in retrofitted buildings, the Swedish system, and greenhouse with radiant tube heater. A relative comparison of the three winter farrowing alternatives is shown in table 1. No system has a clear advantage over the others, but each system has its own unique strengths and management requirements. Producers interested in capitalizing on the growing demand for natural pork born in the winter should consider their individual resources and goals as they adopt a system to meet their needs.