There's 630mg per tablet, should I give her half?
I believe you can actually give a whole one once per day safely - for which I will cite a thread by a well-respected member who cured a more chronic case of shell-less eggs that way using something with the same mg amounts: https://www.backyardchickens.com/th...o-help-an-old-hen-build-an-egg-shell.1522766/
I've just never actually been able to get my birds to eat a whole tablet's worth. Half is probably an easier start given this is her first problem rather than a recurring issue.
If they haven't been touching it, one thing to try with that is to move the container to a place where they spend more time/activity. I don't free range, but the place I've found is to have it well lit and where they are likely to spend time right before going to roost. That'll increase the odds they make use of it vs igoring it because they went someplace else to forage and forgot it exists.I do have some oyster shell bits somewhere in the barn I can give them