Dark Spots on Shell

[Rock Nana]

Within the past week I have gotten 3 smallish eggs with a dark spot at top of shell. I have 2 young pullets ready to lay. Wondering if these are from 1 of them having issues laying or an older hen with health issue. Everyone seems fine, no signs of mites, etc. Any help appreciated.

 

[Chicken Whisperers]

It might be blood. Check their vents to see if it's bloody. It's not rare for a blood spot to be on the shell sometimes

 

[aart]

Does it wash off?
I'd be tempted to candle it to check for porosity...or...
.....break it open and see if shell is thin there.
Blood usually appears as a streak/smear...I think this is just a shelling glitch.
Molting season is drawing nigh, can expect some funky eggs as older birds ramp down production prior to molt.

 

[inbreeder]

Don't have a reply but I do have a question, I have brown egg's and green, todays collection is a concern, the brown egg's have blotchy spots of a darker brown color showing on them, cause unknown to me, this is the first time I'm experiencing this, I live in south Ms. and the weather is hot, but so was last year and the year before that.... sort of looks like the picture posted by rock nana but these I have are larger and on the sides, any help's?

 

[aart]

Don't have a reply but I do have a question, I have brown egg's and green, todays collection is a concern, the brown egg's have blotchy spots of a darker brown color showing on them, cause unknown to me, this is the first time I'm experiencing this, I live in south Ms. and the weather is hot, but so was last year and the year before that.... sort of looks like the picture posted by rock nana but these I have are larger and on the sides, any help's?

Welcome to BYC!
Best to start a new thread here:
https://www.backyardchickens.com/forums/chicken-behaviors-and-egglaying.18/create-thread
with some pics of the eggs in question and info on birds.
Short answer is, in conjunction with what I already posted, coating can change from day to day.