I have been having a long-running spell of one of my hens, Clara, laying soft shell eggs. It has been going on for at least 3 months now. She is nearly 2 years old.
With the 3 hens we went through a long period of just 1 egg per day most of spring / summer, then around 3 months ago the soft eggs started, which makes the laying box messy for everyone else and is causing hygiene problems and is a bit depressing.
The other 2 hens are now laying a normal egg each per day and have been for around a month but still the soft egg comes from Clara every day.
Calcium uptake is provided by Oyster shell grit, ground up cuttlefish bone and ground eggshells, the other 2 hens have never had soft shells using this. All hens have regular access to the back garden and eat a variety of plants and minibeasts as well as their layer pellets and a limited quantity of kitchen scraps.
Clara is an Amber Star.
Has anyone else had this experience?