Thanks so Much!Sorry, forgot.
Calcium dose I use is ~50 mg per pound per day.
One can use human calcium citrate tablets. I stay away from calcium carbonate because I've read that it's not absorbed as easily as other forms of calcium. Of course supplying them with oyster shell is always a good idea, but oyster shell doesn't always help a hen that's low on calcium.
One that is absorbed very quickly is liquid 23% calcium gluconate, which is found in the cattle section of feed stores. Dose for this 0.2 ml per pound *orally* or subcutaneously (injected under skin). Refrigerate after opening.