Wheat berries for chickens?

I don't have a clear answer, but just for what it's worth, I think it would probably be safer to sprout them than to give as is considering the length of time they've been stored.  It's possible there is microscopic mold buildup that could be harmful.  Not saying that's the case; I'm just saying if it were me, I think I'd see if they would sprout or even rinse them in a dilute solution of bleach water and let them dry before giving to the chickens.

If wheat berries is, as I assume, whole grain wheat then I feed it every day. I have not however fed 20 year old wheat. Mold may be an issue but failing that I would assume it has lost considerable nutritional value at this point.

I would see if they sprout or not. If a good portion of them do sprout, they probably still have some nutrition to them, at least enough to get a sprout going. That said, properly stored, seeds can sporut and grow many years later. I think there is a lotus type plant that sprouted after a thousand years of storage. Granted, a wheat seed isn't a palm or lotus seed, but corn can still sprout after 4 years of storage.

since its the whole grain still intact, I would say there's probably some nutrition left.  Wheat berries are the largest ingredient in our homemade feed.  They are a good source of protein and a good grain (I mean wheat is in sooooo many things we humans eat after all).  But, since they are so old, I think the sprouting idea is a good one, though I'm not sure it would kill any mold entirely if there was any.  I would definately NOT put any bleach on them.  Way too toxic.  Maybe a weak vinegar solution and a good dry out.  Not really sure.  I would be inclinded to just give them to them as they are since we feed wheat berries all the time....esp if they look good and don't smell funny.

Oh, to clarify, I meant see if they can sprout, and if they can, go ahead and feed the unsprouted grain.

I'm guessing by your location that you are in a dry climate.  And this food was being stored for human consumption by someone who is familiar with that practice.  I have also picked up a  few buckets of oats and wheat stored the same way and have fed it with no trouble.  Wheat is generally high in protein, the very reason it is a grain of choice to store in case of emergency, however after so many  years it has lost some oomph.  As long as it smells fine, has been kept dry, etc...I see no problem with feeding it.