You're having that problem too? I've been cursing up and down and sideways (that's what that blue cloud over NE TN is) because the ones I bought from Lowes had grass seed in it and back in the fall I put them on the beds and now there's grass coming up in the beds! Blast! I complained to Lowes. They ignored me. My solution was to cover the raised beds with black plastic to kill off any of the grass seeds because all attempts to pull them out of what's left of the flakes just yanks the flakes out of the bed. The amount of waste is terrible. I had to recycle them into the compost pile. Grrrrr.

Can you put your goats onto it? Also in the case of Nayan's comment, you can treat the sprouts as green manure. Turn them back into the bed with a pitchfork or shovel. It will feed your crops.

I tried straw bale gardening a few years back, and all was going swimmingly until my bale started sprouting tons of seeds. A couple years later I read about solarizing garden beds to kill any weeds and weed seeds, and I wondered if a straw bale could be wrapped in plastic and solarized in the same way. I've never tried it, but you're more of an experimenter than I. If you try it, please let us know the results!