One of my four Barred Rocks are layed a shell-less eggs
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Are these coming from a girl new to laying? If so, that should correct itself with a bit more time. Sometimes it just takes a while for their 'apparatus' to fully mature.
Whether new to laying or not, be sure to have extra calcium available to all your layers at all times. Crushed oyster shell is good for this.
There can be other reasons why shell-less eggs happen, see this article from the Learning Center. Maybe that will help you narrow down the cause:
You betcha! Isn't it fun once they start laying? Sort of like finding little presents every day