This hen is one of our top hens, she is usually the one doing the running off, I just don’t think she’s actually eating the available supplies. I’ll see how the calcium supplement helps her and if it doesn’t give her any better shells then it’s definitely a reproductive issue, which is possible.I was getting some shell less eggs, some whole some that had broken, as well. I don't know which pullet was having the problem. I have a bowl out of oyster shell out for them at all times but what I decided to do was put out a 2nd bowl. Just to rule out any possibility that maybe they were being run off from or just not getting enough for whatever reason of oyster shell. So far, I have 1 pullet that is laying eggs with some calcium buildup on her eggs and all of the rest are coming out solid so far. Haven't had any more soft or shell less eggs. Not sure of your setup but thought I'd share an easy fix that so far is working for me.