I had one that was laying rubber eggs (shelless eggs). not sure what was causing it, plenty of calcium and layer feed ect. But I had another problem with one of my other chickens, she was pulling all the feathers off the others. It could have been due to low protein, so I upped the protein for all of them, meal worms and boss as treats along with scrambled eggs every other day, no scratch. Still working on the feather puller with pinless peepers, I think it just developed into a bad habit, however, the extra protein really helped with the rubber eggs. I do not get any anymore and all the girls' shells are very thick.