The experimental data obtained from the tests conducted on a newly developed heated-air batch hay drier described in Part 1 of this paper were used to validate a computer simulation programme for the drier. The computer simulated and measured temperature data at various locations for the drier agreed reasonably well. The simulation programme was subsequently used to optimize the drying system for minimum total drying costs within set bounds of drying time and overdrying for various initial moisture contents of hay, airflow rate, drying air temperature, hay stack height and batch size. The simulated results are presented as an aid in the management and operation of the drier and as a guide in the design of similar new batch hay driers.