This paper conducts a stated preference method study to elicit Korean consumers’ WTP for milk produced under the conditions of farm animal welfare in Korea. We recognize that it is necessary to address the respondent uncertainty issue directly because animal welfare is a new issue to consumers in East Asian countries, and thus suggests a hierarchical ordered probit (HOPIT) contingent valuation model where the WTP function is completely identified and the monotonic relationship among choice thresholds is always imposed, even when there are individual variations in the thresholds. It was found that consumers’ WTP for animal welfare is substantial in Korea. Incorporating respondent uncertainty changes the WTP estimate. Moreover, individual respondent characteristics affect re-spondent uncertainties significantly even when they do not affect the WTP function directly, emphasiz-ing the importance of accommodating individual heterogeneity into the random valuation model.