<P> Hay can be raked into rows as it is cut, then turned periodically to dry, particularly if a modern swather is used . Or, especially with older equipment or methods, the hay is cut and allowed to lie spread out in the field until it is dry, then raked into rows for processing into bales afterwards . During the drying period, which can take several days, the process is usually sped up by turning the cut hay over with a hay rake or spreading it out with a tedder . If it rains while the hay is drying, turning the windrow can also allow it to dry faster . However, turning the hay too often or too roughly can also cause drying leaf matter to fall off, reducing the nutrients available to animals . Drying can also be sped up by mechanized processes, such as use of a hay conditioner, or by use of chemicals sprayed onto the hay to speed evaporation of moisture, though these are more expensive techniques, not in general use except in areas where there is a combination of modern technology, high prices for hay, and too much rain for hay to dry properly . </P> <P> Once hay is cut, dried and raked into windrows, it is usually gathered into bales or bundles, then hauled to a central location for storage . In some places, depending on geography, region, climate, and culture, hay is gathered loose and stacked without being baled first . </P> <P> Hay must be fully dried when baled and kept dry in storage . If hay is baled while too moist or becomes wet while in storage, there is a significant risk of spontaneous combustion . Hay stored outside must be stacked in such a way that moisture contact is minimal . Some stacks are arranged in such a manner that the hay itself "sheds" water when it falls . Other methods of stacking use the first layers or bales of hay as a cover to protect the rest . To completely keep out moisture, outside haystacks can also be covered by tarps, and many round bales are partially wrapped in plastic as part of the baling process . Hay is also stored under a roof when resources permit . It is frequently placed inside sheds, or stacked inside of a barn . On the other hand, care must also be taken that hay is never exposed to any possible source of heat or flame, as dry hay and the dust it produces are highly flammable . </P> <P> Early farmers noticed that growing fields produced more fodder in the spring than the animals could consume, and that cutting the grass in the summer, allowing it to dry and storing it for the winter provided their domesticated animals with better quality nutrition than simply allowing them to dig through snow in the winter to find dried grass . Therefore, some fields were "shut up" for hay . </P>

What are the big rolls of hay called