The soft shelled eggs are just your sully getting the reproductive tract going. I have never seen or heard of them being viable. Young chickens will also lay eggs with no calcification (shell) when just getting started laying. It can happen any time, but most common with first year layers. Not at all an indication of low calcium or D3. Just a young reproductive tract. Greg - @ALDABRAMAN just had a female lay a few of those shell-less eggs.