If they have access to the grit free choice, that's enough. The grit stays in the gizzard quite a while, they don't have to ingest it at the same time as they eat. Since it stays internally, a little goes a long ways.
I noticed the title of your thread when I came here to take a break from cooking/baking. We had a fridge/freezer combo die on us recently and just found it this am, so I've been cooking/baking everything salvageable. Stuff too thawed to chance went to the flock--boy, are they happy birds today! I've got two venison livers in the sink, waiting to be cut up a little to go to the flock and the dogs. Fortunately, it was mostly a storage freezer, to keep bugs out of things that don't necessarily need to be frozen, but there was a crapton of zucchini and berries in there. I've baked zucchini muffins and berry cobblers galore today--my friends are also going to be happy tonight!
edited for post-chemo spelling lol
