Fig. 7.

Reduction of infected dust between cohorts that is required to reduce the probability of an outbreak in the next cohort to 50%, 95%, 5% (dots, upper and lower confidence intervals, respectively). Farms are small (5000 birds at 5 kg/m²), medium (20,000 birds at 20 kg/m²) or large (30,000 birds at 35 kg/m²). Birds are either all unvaccinated or vaccinated. Cohort duration is 30 days. (a) Unvacc. small farm, (b) unvacc. medium farm, (c) unvacc. large fram, (d) vacc. small farm, (e) vacc. medium farm and (f) vacc. large farm.