Hen laid just a withered, deflated, empty shell?

[doughouse]

How old are these birds and how long have they been laying?
What all and how exactly are you feeding?

They're all the same age, just a few weeks shy of one year. They started laying in the fall, although egg production dropped dramatically during the winter. Their feed is 16% protein in a treadle feeder, they free range for large parts of the day and they have access to free choice oyster shell.

 

[doughouse]

Yesterday we had our first four egg day from our flock of four, so I know whoever laid this one is back to laying normal eggs, so hopefully that's a good sign!