Yes. A human that takes large amounts of a calcium supplement can develop kidney stones. Hens can also develop kidney stones. Not something you wish to do on purpose.
Long term use of a calcium supplement, other than oyster shell, is discouraged as it's very hard on the kidneys.
I also have a hen with chronic paper thin shells, and I and she just have to live with it.
Here's my tutorial on why chickens have an easier time swallowing a bulky pill than humans do.
We think chickens must have a problem swallowing a large pill just because we do. But their digestive process is different from ours. We begin the digestive process by chewing first, then swallowing...
Give one calcium tablet once a day for as long as it takes for her eggs to develop a normal shell. Usually, a week will do the trick, at most, two weeks.
First of all, calcium gluconate has far less calcium than the carbonate or the citrate forms. Therefore, to get the same effect as citrate or carbonate forms, more gluconate has to be given. It's still a fine calcium to give, and if it's easier to give liquid to ducks, then let's do that...
Just a while ago here on this forum we were discussing how much calcium to give a hen, and some of us were astonished to discover that we were reading the label on the bottle of calcium wrong. Up until now, I, and also quite a few other people, have assumed that when the label on the front of...