i got grey some cuttlebones, just to be on the safe side, and hung one in his cage today. he paid attention to it and started chewing smalls bits off and grinding them. seems to be normal, but i just want to know.. when is it too much? i read that an overload of calcium (even just 1% above) can cause serious health problems for an african grey. how can i know if he's fine with calcium, or if he's taking in too much?