Actually, a collapse of agriculture is good for peasants : the lands that fell into disuse were the least productive ones, marginal lands that had been cultivated because of population. Thus work was quickly much more productive, and by 1450 most land workers ate meat regularly. During the collapse, the rough times came not because of economics but because of politics, warrior bands roaming the lands, and illness with the repeating plagues.

Note that the history Migeru quoted about labourers getting better wages dates from the 1370's ; pretty much the early phase of the collapse, as population continued to decrease into the fifteenth century.

Un roi sans divertissement est un homme plein de misères