Did my chickens eat all of their oyster shell?

[Blackberry18]

Yesterday I got some oyster shell for my chickens. I hadn't fed it to them in a while, and just put it in a bowl in their outside area. Then this morning, when I came out to feed them, oyster shell was scattered on the ground around the bowl, but the bowl itself was exactly like I left it, except empty. So, did my chickens eat all of the oyster shell? I have the idea that it doesn't taste as good as food, so unless my birds were seriously calcium-deprived, I don't know why they'd eat it. I left it overnight outside, so I suppose some wild animal could have gotten at it, but again, it doesn't taste good, and the bowl remains upright. My birds weren't scratching at it, and there isn't as much around the bowl as I put in in the first place. Anyone have an explanation for this?

 

[sourland]

Birds may very well been low on calcium or grit. Oyster shell fulfills both needs.

 

[Blackberry18]

Birds may very well been low on calcium or grit. Oyster shell fulfills both needs.

Should I allow them to eat that much? I'm worried they might overdose on calcium.

 

[ChickenCanoe]

They won't overdose on calcium as long as it is in a separate container.

After all, if it is as distasteful as you believe, why would they eat so much?

They don't really scratch at it. They eat a couple bites when they feel the need. It is entirely possible they kicked the bowl over and turned it back upright. I use cage cups attached to the side of the run or coop so they can't be overturned. When I just put a container in, they turn it over and it gets strewn into the bedding.

Oyster isn't exactly the same thing as grit nor is it interchangeable.
People call it oyster shell grit but in the truest definition of the word, it isn't grit.
Oyster shell is soluble, meaning it dissolves in the digestive system once it gets moistened and contacts the acidic digestive components therein.
Grit, on the other hand, is insoluble stone that remains in the gizzard for a long time aiding in grinding feedstuffs.
Oyster shell is softened enough by the time it gets to the gizzard isn't hard enough to grind anything.