>>96843709
Why would a normal farmer want to have actual witchcraft and zombies plowing the fields for him? Literally stinking miasmic corpses spreading disease, animated by dark, evil powers... it's bound to give people the creeps. Not to mention if the servant is someone they knew.
What makes you think a decaying body will be effective under the summer sun, with crows, locusts, fungi and other pests that roam the fields?
Is it even cheap to animate them?
From a meta perspective, it's better to leave necromancy and magic in general as rare rather than commonplace. If people get used to it, it stops being impressive and mysterious.