eww, what's that smell?!

I just popped my newest fluff in the wash--brand new/never worn--Mutts and Dream Eze AIOs. When I went to the wash to get them, they stink like wet hay. I know Mutts have hemp/velour inners (with hidden bamboo) and Dream Eze has organic cotton inners. Is it the hemp and bamboo I'm smelling? I'm stoked about these natural fibers (we have a lot of microfiber in our stash) but I wasn't prepared for this smell....... I'm washing 'em again.