"Didn’t the birds already eat it?
Ha! No, my wife put a small amount in one of her bird feeders. They have not touched it. I have about one pound (+/-) left."
I've had similar experience. Animals don't want the spent grain. That's why I now use my spend grain for making bread, pretzels or as fertilizer, mulch in the garden.
my chickens and the deer love spent grain so much I have limit how much they get