I only give tums when it appears that a hen is struggling/possibly egg bound. Not as a daily supplement. Usually when they are just coming into lay.
My LH during this years molt stopped laying completely. When she started up again her shells were thin and pink! That’s right a LH that lay’d Pink thin shelled eggs. I thought oh no...blood in her egg shell gland? Perhaps as a prolific layer we were on a slippery slope of reproductive problems.
Then I started really watching and found out they were getting into the cat kibble. You know the kind that has every artificial red coloring dye known to man in it. (I use it in traps)
So....3 months later her eggs are still not as white as they were when she was younger but they’re better and her shells are hard again. Definitely not the same in size of egg.
I wonder if that was the problem. Too much protein and food dye? The other girls are younger and I wouldn’t of noticed a color change since they lay pink or brown eggs anyway.
I wish there was a definitive answer. Some chickens just have issues where others do not. We get attached cause they are just so fun and amazing. We all know what it’s like to worry and feel a bit helpless
With my brats (sneaky booger’s) I honestly believe they kept a lookout for me and would eat the kibble like candy.
So if you can spend sometime watching your “softy” layer she might be into something that disagrees with her system.
I offer yogurt (low-fat vanilla Greek yogurt) mine absolutely love it. But...I have one that has difficulty with the lactose in it. So...it’s always going to be something with chickens. I hope you figure out what is going on with your girl.