What or who does 'the rick-thatcher' refer to in Middlemarch by George Eliot?

Here is the full quotation:

No matter what a man is—I wouldn’t give twopence for him”—here Caleb’s mouth looked bitter, and he snapped his fingers—“whether he was the prime minister or the rick-thatcher, if he didn’t do well what he undertook to do.

thatch

to make a roof for a building with straw or reeds

-Cambridge

rick

a stack of hay, corn, straw, or similar material, especially one formerly built into a regular shape and thatched.

A rick-thatcher would thatch rick (or stack).

Until the middle of the last century, perhaps more than half of all the thatching carried out in Britain, was this type of work… Stacks and ricks dotted the countryside and filled the farmyard. Cereals of every type were stored, awaiting the thresher; hay was kept dry for a winter’s feeding; all safe under a thatched covering. This employment kept the craft alive, when domestic thatching was in serious decline…