Grey stain/spot on Pekin duck eggs

[Chelseasducks]

I've noticed a few of my Pekin eggs have a grey stain. Are these edible? Any idea what is causing this?

 

[Crazy Maizie]

Just looks like excess bloom.

 

[The-White-Elephant]

I've noticed a few of my Pekin eggs have a grey stain. Are these edible? Any idea what is causing this?

Have you ever gotten this before

 

[Chelseasducks]

Have you ever gotten this before

No, this just started happening the last week. Only change is the weather. We have had the first bit of snow but no changes in food.