Do any of the others that belong to kaks give them oyster shell grit? And do they eat it? I have it in my large cage and always have but to be honest I only ever have to empty and refill the bowl when it gets pooped in! The only one who shows it any attention at all is little Chicken. He seems to have a bit of a nibble most days but the others completely ignore it.
To be honest I don't know if mine eat it. But I mix a kilo of it in with 20 kilo's of seed - I don't have it separate. Alot of people say birds who hull their seed don't need shell grit, that may well be but I have always provided it - that or mineral sand.