How long is dry good for

A friend gave me a great deal of dry Purina One.  I plan to use it for the barn kitties.  It wasn't in a bag but in a plastic tote. 

She lost her cat last August, so it is at least that old.  Any ideas whether I should use it or not?  It is dry and smells fine, and looks good.

Thanks.

I would guess it is fine, the best by date they print on the bag is well over a year. It is dry and kept from the elements in that container. I store my pet food in empty Tidy Cats litter tubs, and it stays good in there. I have only sen dry food go bad once, I had put a tub of it in the outdoor storage when one of my cats would start losing fur when she ate it. It had been about 2 years when I rediscovered it, lets just say it was not too pretty.

It should still be just fine. Your cats will let you know if it isn't by just plain refusing it.