One other comment- it is haying time in England, fall having arrived for the last real “cut” tedding, raking and baling. Round bales were invented for ease and for preserving of total digested nutrient protein. As tight as one wants to get a square bale, they lose their TDN fairly quickly. In the states the “shelf life” of round bales is improved with waterproof covers wrapping them. This for the benefit of cattle, dairies, etc.
Leaving the hay bales outside vs. barn storage has a lot to do with nutrient loss, and labor.