Have you tried willow toys for chewing? Those are a big hit with many bunnies! They’re available on this site and other websites around the internet.
I have only seen my buns eat their cecals (night droppings that contain nutrients) maybe a few times. They typically never even touch the ground, unless there is a dietary imbalance and they are overproducing them. A bunny will bend over and you may see her moving around down there and then she straightens up and she’s chewing. They can actually eat the cecals directly from their anus. (I know… icky, but that’s what they do.) So I’m not surprised that you are not seeing this take place.
The bigger concern would be if there were droppings around the cage and they were not getting eaten at all. And now that I’m thinking abut it… I may have misunderstood your post… lol. Are you saying this is the case and the cecals are there but she’s not eating them? Or you don’t even see them?