What kind of crumble...brand/model?
...or look at tag sewn into bottom of bag for protein and calcium percentages.
Cut out all the scratch, herbs, and seeds for a week or two. Mealworms are good tho.
New pullets don't always 'get' eating the OS.
I sprinkle a few pieces on top of the feed...
Broken, not hatched ;)
That is a broken soft shell egg, just membrane and no shell.
Pretty common with new layers, eating them will not automatically make them egg eaters. That one has not been eaten or you probably wouldn't even have noticed it.
She may need more calcium, or fewer treats, or it...