Why do you want to delete it?
How old are your hens (the one with pale comb, and the other 2 who are laying shell-less eggs? What is your general location? What are you feeding them: Protein content of your layer, mill date on the current bag of feed, how much scratch are you giving them in relation to their layer? Feed available all the time, or are you feeding them a set amount? Do they free range or are they kept in coop/run?
Suggestions:
Get a fecal float done on your flock. Be sure to include poo from the 3 problem birds.
If they are in a coop/run set up, convert your run to a deep litter run.
Be sure your feed is at least 16% protein, and limit the scratch to an occasional, not even daily treat. You could even give them small amounts of kitty kibble which has lots of animal protein. Use this short term, not as a regular part of their diet.
Consider fermenting your feed. There is a how and why article, not written by me in my signature.
Add some multi vitamins to your bird's diet. The gals who are laying shell-less eggs may have a shell gland disorder or a metabolism disorder. Increased vitamins might help.