Change in egg coating/color

[twistedwire]

One of my red star hens has started laying funny looking eggs-they are the normal rich color, but it's like they are coated with a thin whitish layer or something. Today's egg was a bit smaller too.

Yesterday I flung the egg over my fence, but today I kept it.

Thoughts?

 

[weeders n feeders]

Extra calcium. It fine. Just on the shell.