Also - calcium citrate is supposed to be more absorbable, at least in humans, and the D3 helps that too. I think @micstrachan , or maybe @RoyalChick, just pops a pill in. Certainly quicker. Also one of them found there is calcium powder available online. But I also suspect the hens like the fruit flavor of the Tums. At least @Kris5902 found a flavor preference, that's partly why I throw them in.Wow that is an extended chow session!
I make mash balls of the feed they're eating, so here it is feather fixer or All flock, or sometimes Exact baby bird formula. Mix with some greek yogurt and crushed/ground combined Calcium Citrate w/ D3 and fruit-flavored generic Tums. Let it sit, maybe add more feed to thicken, and mix again to be like putty. The later mixes really smooths it. Then I form balls of various sizes, each hen likes to deal with them differently..
These days I am not putting in the calcium powder but continuing with the mash balls, because they like them, the yogurt might be good for their crops and all, I want to maintain some consistency with foods they like, and I like holding the dish and letting them take them out but I also hand them out, encouraging each one to get some, and especially now I want to make sure Peanut eats some (very concerned for her that she keep eating with this hard molt, she is quite naked. This afternoon she ate only four, and she usually goes to town with them. But this morning she ate some sardines too).
Dose of calcium powder mix: I figure two Citrate+D3 pill = 500~600mg calcium citrate and two Tums (high-strength) is ~2000mg calcium carbonate, and when I took those ratios and ground up a bunch in a small (dedicated) coffee grinder I found in two level teaspoons they were getting that 2500-2600mg total. And that would be 650+ mg per hen assuming they all ate the same amount, which isn't the case of course.