organic piglet producing herds are able to sell less pigs for slaughter at time of reduced market demand, these organic breeding herds may have difficulty selling gilts as breeding replacements. In areas with a relatively high density of pig herds (e.g. in The Netherlands) problems arise in case of disease outbreaks where transport of animals is prohibited. Finally, discussions with Dutch organic herdsmen made clear that for health security reasons they preferred a 'closed' breeding structure as opposed to an 'open' structure.