One of the really odd notes about the plague is that, from what we can tell, farming wasn’t much affected by the rapid rate of human and animal death. That is, we only know what the manor harvest record books tell us, in the cases where these books have been preserved through fire, mold, and revolution to the present day.
We’d expect that the plowing didn’t get done, the sowing wasn’t completed, and the harvests weren’t collected. Human death rates were at least 30% and in some cases as high as 60%. Some tiny villages closed up when the survivors had to move, being too few to keep the settlement going. These villages were often staging bases for farm workers to walk to their fields.
There’s a kind of economics study that deals in historical problems, trying to reconstruct what probably happened. Using what we know now about prices and markets, they look at the clues from the past and assemble a reasonable guess. Other historians then look at period art or archeology and try to confirm these guesses. At some point, we feel that we “know” what happened and can say so with reasonable confidence.
The conclusion that these studies have come to, concerning the Black Death, is that Europe was over-populated in 1347. Of course, it had far fewer people than it does today. It was over-populated specifically for its ability to grow food; it may have been over-populated for its infrastructure, too. We know that they were running out of wood, since so much wood was being turned into charcoal to make iron, which then replaced wood in buildings. We know that the rivers were over-flowing with sewage.
We know that the European diet before the plague had become sharply divided between rich and poor, with the poor eating very little meat, mostly legumes and coarse grains. Normal people ate two meals per day; they went straight to work in the early morning and only ate breakfast around 10 am., which then allowed them to work until sunset, when they ate again. There was no spare food to carry along in a pouch for “lunch.” A third meal was only invented in the next generations, when diet had changed after the plague.
As far as we can tell, field work never stopped because no matter how many people dropped dead, there was generally someone else ready to take over. What were these people doing before their friends died? We don’t know. Medieval Europe didn’t count “unemployment.” It showed up mainly in hunger: and we do know they were hungry.