Deposits on outside of egg

[Babycat ranch]

My Silkys are laying an egg with hard little deposits on the outside - it is nearly daily so it seems to be the same chicken - only 1 egg has it from this pen

 

[nchls school]

While not common, it does happen and may quit as the hen continues laying.

 

[SurferchickinSB]

My Silkys are laying an egg with hard little deposits on the outside - it is nearly daily so it seems to be the same chicken - only 1 egg has it from this pen

Excess calcium deposits,