The "marshmallows" (what my son called them) are mostly for fermented hay, called haylage. Like silage. Can't be fed to horses, no more than silage can. Horses have a VERY delicate digestive system compared to other domesticated animals.
If the plastic remains intact, it makes an acceptable mulch for the garden. They are just very heavy and I don't have a way to move them.
Oh thanks for that info. I know my cousin is very careful what she feds her horses. She talks about the first cutting , if done at the right time, the protein content is high, if cut and left too long because of rain, it loses a lot of that protein. It's been a lousy year for haying. Too much rain.