Need help with laying issues

[trixiekj]

Purina's layena crumbles as the base plus I mix in probiotics, flax seed and some herbs.

 

[trixiekj]

Ok, thank you!

 

[trixiekj]

I have a cream legbar about 10months old and she has laid nice blue eggs until a month ago. Her last egg's shell was so thin it cracked then she stopped laying. She laid a shellless egg today. She's on quality layer feed and has free access to oyster shells. Any ideas what could be happening? She has been wormed naturally with a worm tonic as have the other 9 chickens. I'd appreciate any thoughts.