Hickory nut question

[Snicker Bar]

It's early spring here in MS. We have a lot of hickory nuts on the ground, most still in the big black shells, but some are splitting open. I gathered several; and when the outer shell is peeled, I break the inner shell (with hammer, those suckers are hard!) If outer black shells are black, but the inner shell is still hard; ( not black and gooey), and the nut inside looks ok, are these safe to feed? And is it really true, no acorns! We have so many of those also