One of my hens, haven't determined who, is laying a thin shelled egg. there's been at least four or five. Everyone else's shells are fine. Wondering if it can be related to two of them getting their tail feathers ripped out by a dog coming onto the property. They are making new feathers.
Most definitely stress can play a huge part of egg laying and issues. You can offer oyster shells to them or their own egg shells smashed up. They will only eat what they need. I would also give them a little extra protein to kick start the feather growth. A scrambled egg or meal worms are a proven favorite by me. Hope this helps.
Did your girł(s) start laying normal again? One of mine consistently lays thin shelled, only one, of 16, so diet doesn't seem to be a problem. It's one of two girls, that much I know, and neither are bullied or unhealthy in general. Just curious if your problem resolved? Hope to hear from you, thanks!