To make sure pallets can be both extruded and transported from the granule source, a certain form and size is required. This article explains how.
Concerning pellets, oval or cylindrical are preferred with a max size of D1=~3.2 mm D2=~2.16 D=2.46. The pellets can have a maximum deviation of +0.15 mm. If the pellets are within these specs then you should encounter no transport problems.