Since the 1960s pig farming has become increasingly industrialized.
Modern pig farms are typically composed of indoor barns each hosting pigs in a specific stage of the production cycle.
Grower pigs are generally raised in group housing in closed barns with slatted flooring. Sows are kept in group housing, until being moved to farrowing pens where they remain until piglets are weaned.
As an alternative to indoor rearing systems, pigs can be raised outdoors either for their whole production cycle, or during part of it.
The two main pig production stages which can be carried out outdoors
- Reproduction: sows and piglets can be kept in outdoor housing facilities, with individual farrowing huts. In some climates, such housing is appropriate for use only during part of the year. In the UK, it has been estimated that 40% of the breeding herd is kept in outdoor housing.
- Growing/finishing: all or part of the grower/finisher stage of a pig’s production cycle can be carried out in outdoor group pens.
What are the main advantages of outdoor production systems?
Outdoor production systems provide many welfare benefits to pigs.
In general, such systems offer more space per animal as well as better air quality. In fact, pigs raised outdoors tend to spend more time exploring and feeding. Such behaviors are signs of wellbeing in pigs. Additionally, outdoor rearing systems offer some benefits to pig health, such as lower impact of respiratory diseases.
What are the main drawbacks of outdoor pig production systems?
While outdoor pig husbandry systems offer many advantages, particularly regarding welfare, they also have several downsides.
- Efficiency: Pigs raised outdoors tend to have lower levels of both reproductive and growing efficiency than indoor raised pigs. This is partially due to the increased energy expenditure of pigs raised outdoors, and the subsequent increase of feed intake.
- Biosecurity: biosecurity is a major issue for outdoor pig husbandry. Facilities are more difficult to clean and disinfect, making true eradication of pathogens difficult if not impossible. Furthermore, pigs raised outdoors are more likely to encounter wild boars or other wildlife. This can facilitate the transmission of infectious diseases, most concerningly African Swine Fever.
Outdoor pig production systems represent an alternative to the more common intensive indoor systems. If managed correctly, such a system can greatly improve animal welfare. A niche market is slowly growing in many countries for pork from pigs raised outdoors for at least part of the production cycle. This is due to increasing awareness among consumers concerned about animal welfare and food quality.
Park, H.S., Min, B. and Oh, S.H., 2017. Research trends in outdoor pig production—A review. Asian-Australasian journal of animal sciences, 30(9), p.1207.