Figure 1.

Total number of animals per group that were infected post‐challenges as determined by virus shedding and seroelevation. A chicken was considered to be shedding if virus was isolated from oropharyngeal and/or cloacal swabs on at least one occurrence. A four‐fold increase in HI titer 14 days post‐challenge (compared to pre‐challenge titer) was considered to be seroelevation suggestive of infection. The total number of animals infected per group is the combined total of animals that were shedding and/or seroelevated after challenge. Groups are as described in Table 1. Group 1, n = 9; group 2, n = 9; group 3, n = 10; group 4, n = 11; group 5, n = 11; group 6, n = 10; group 7, n = 10; group 8, n =11.