Medieval Haystacks

Whether it was feed for warhorses, or rushes to cover cold castle floors, hay is ubiquitous to medieval Europe. Hay would be sun dried and piled into stacks for storage. This was a task for trained laborers, as the stack would need to be waterproof to survive. Although dried, the compression caused by being piled high (plus gravity) would further "cure" the hay. Haystacks could and would be elevated with wooden platforms to allow better drainage. Some would  be thatched on top to protect from ot