What do these zits on my eggs mean?

[Headers Hen House]

Lately, one of my girls has been laying eggs with these weird zits on them.

What does this mean?

 

[AlleysChicks]

Just extra calcium added on the egg shell.

 

[sumi]

Calcium deposits… See here for causes: https://www.backyardchickens.com/articles/common-egg-quality-problems.65923/