To calculate the probability p i that a particular proactively culled farm i was infected, we need to adjust the infection hazard by the probability that the farm would have not been reported as a clinical case before its culling date T i c . From the outbreak data, we calculate the probability density of the time from infection to report for reported IPs and hence the cumulative probability distribution of the time from infection to report, denoted by F. Then, with l i (t) being the force of infection on a proactively culled farm i at time t (from the best fit model conditioned on 23 rd February), the probability that that farm gets infected and escapes reporting between its potential infection time and culling time T i c is