Most breeding organisations can supply breeding stock that is deemed to be EP free and so a new pig farm can be set up or an old one repopulated EP free. The question is whether it will remain so. One rule of thumb is that if you have an uninterrupted view of an infected EP herd, particularly if it is less than 3km (2miles) away, there is a definite chance that sooner or later your herd will become contaminated by wind-borne infection. If the herd you can see is a grower/finisher as distinct from a weaner producer than the risk is greater. The risk also increases the larger the infected herd. In a pig dense regions such as in the pig rearing areas of Eastern England, Germany, the Netherlands, Belgium, Eastern Spain, Quebec or Japan, it is impossible to remain free. You are likely to remain EP free indefinitely if your EP free herd is in a region of low pig density, such as parts of North or Southwest France, Northern Spain or the West USA. Likewise if the land is hilly or mountainous or on a sea coast.