Also, check out this feed first! Read their labels, ask questions, find out mill dates. Try a small amount first, if the data looks good. And do check out local mills too. There are local mills that might have good products, or not. And most will sell mash only, because the equipment...
I think it would age out before being used up, and will be difficult to store safely too.
Forty bags of feed? I see twenty metal garbage cans, or a metal lined vault, or how many old chest freezers?
Using feed up within three months of it's mill date would be best. We try to use it within two...