I am kind of confused by this statement. The laying hen is the one not getting what she needs.It is better to weight on the side of caution that on the side of error. If you are already feeding starter then why have extra that can affect them in life, as opposed to NOT having it there and they already have what they need from the feed.
Yeah, I think you are right about this when you feed layer feed all the time to young hens, but I can't sign off on oyster shell being present being able to do that. Why would hundreds of people be telling others to use oyster shells and all flock feed instead of hundreds of people warning others that this act would cause deformed birds?Never said it was life threatening. I said it stunts their growth. That can be anything from not being able to lay or have any number of disabilities.
It depends on how many eggs the hen lays. Is it is a heavy layer, then yes, it will be hard for her to keep her calcium at what she needs it to be. I have seen that time and time again. In a natural state hens lay less eggs, thus they don't need supplementation. Our backyard flocks are not nature, though.It doesn't take long at all for the hens to get back up to the calcium levels they need to be at. Heck they don't even really need that extra calcium in the wild. It's not like they have bowls of shell out there.
I am not trying to attack you or tell you that you're all wrong or something, I just want to make sure the OP has both sides of the coin so they can make their decision fully informed.