Oh my godness my Grandma and I have a barnyard baby shower cake this weekend and Im in need of some advice on how to make some hay bails or stack or something for this cake any ideas

What size do you want them to be? For medium bales cut rectangles of cake OR stack cookies like 'nutterbutters'; For smaller ones put together 2 lg marshmallows. For bigger haystacks bake cakes in cups or a mini doll skirt pan. Each of those ideas is covered w/'strings' of brownish/yellow icing.

thankyou so much your advice was a great big help

Maybe you could try to somehow cover the cake with Shredded Wheat cereal to give it the texture and look of hay. It was the first edible thing with the texture of hay that popped into my mind (LOL)!

I've used rice krispy treats covered in fondant for hay bales. I randomly scored the fondant to give a hay texture. You old also use a clay extruder or clean garlic press to make hay.
Hope this helps!