The type of collector will determine the source and number and type of poultry collected. These processes are represented stochastically in the model by sampling from probability distributions. The prevalence of disease at
source is estimated at two levels, village and within village. Within village prevalence varies according to the source
farm, where differentlevels of disease are expected atthese locations. Monte Carlo sampling determines whether village
and source farms are infected based on the estimated prevalence. Based on source farm prevalence Monte Carlo
sampling determines whether a bird collected is infected, and the number of infected poultry carried by a collector is
totaled. Due to the short periods of time poultry spend on transport to their destination (averages 30–60 min according
to expert opinion and surveys) the transmission of H5N1 between birds is considered negligible.