They cut their willow a lot bigger then others so can get a bigger edge to start with. They air and kiln dry the willow to aroun 8% before machinging to their standard shapes. Once they have the rough shape they go in to the dry room to keep at a constant moisture content. The main factory isnt heated so they would pick up the moisture pretty quickly if they didnt have the drying room especially in the winter months.
They are making some very good bats at the moment.
Ps. i've had a peak at some special stuff last time i was there. some of the blades had an 80mm edge!