Do you have oyster shell in the coop that they can help themselves to? Tums is calcium carbonate. Citracal is calcium citrate with D3, which is more readily absorbed and used by the body. Since you're still having problems it might be a good idea to switch to the Citracal or a generic equivalent.First egg that hasn’t busted in the coop since the 24th. Still feels thin shelled. I gave them some tums mixed with sunflower seeds, peanut butter, and egg shells this morning.