BREAKING DOWN 'Unintentional Tort'. In certain cases, a person causing an accident may be held legally responsible for their negligence and may have to pay a plaintiff for physical injuries, property damage and/or financial loss.
Straw is normally used for a bedding material, while hay is used as a feed supplement. Straw is dried out and works well for building nests and providing cushioning for animals to sleep in. It is not moist like hay and is unlikely to mold.
If you ever attend the hay markets you'll notice potential buyers examining the hay (or straw) for quality. Horse hay can't have mold or mustyness. Dairymen usually buy hay based on protein(Nitrogen % x6.25) and energy(inversely correlated to fiber/muturity). What is quality for our mulch use is somewhat similar.