when my parents had the feed mill they produced both crumbles and pellets out of the same mill. I can remember the pellets being made forced through a grate of the approriate size, they made horse nuggets and other pelletized feed there as well just changing the mixes and grate sizes to suit but I was too young to remember exactly how the crumbles were made, maybe they were hammer milled (cracked) after the pelleting process but I do remember them coming from the same machine.
So if the feed store has one they should have the other but basically the only difference is the presentation.
In saying that I feed crumbles now as it suits my feeder system better than the pellets.