When I was trying to figure out what was wrong with one of my hens (was an internal layer, we found out, and later did die from it) the Tums was recommended by dhlunicorn, who probably has some article to back that one up, as she does most everything. This was last year sometime. I have tried the oyster shell in oatmeal and yogurt, the powder that comes off the shells anyway, but they refused to eat it, probably because of the chalky taste. That was not to be a regular thing, just a "maybe it will help" last ditch effort with this hen. She did temporarily get better and then months later, was too ill to continue.
