What is wrong with my Red Sex-Link Eggs?

[MAT10]

My hen is 18 months old and has been an egg every day since she started laying. More recently, maybe last 2 months or less, her egg shells have been very thin and are usually cracked and more often just broken. Beginning this spring, I noticed she was losing feathers. Not sure if it's henpecking or possibly a molt? I don't know. I do know she is on the bottom end of the pecking order. Her eggs have also had a very dark, like bloody spot on one end, consistently, when intact. Don't know what that means either. She still lays pretty much every day. She has free choice calcium and eats the layer feed. I also tried calcium supplements but didn't see any changes in her eggs. The egg in the picture is one I collected just this morning.
I don't know what I can do for her. Can anyone help?

P.S. all but two of my other hens also have feather loss around their neck, especially my lavender orpington. I'm thinking possibly stress or maybe the heat or stress from the heat fluctuation?

 

[sourland]

The two hens without feather loss are very likely feather pecking/plucking the others.

 

[MAT10]

My LH looks pretty good but seeing a slight loss in the front neck of my BO. Otherwise full & fluffy.
I believe she may be the alpha hen.

 

[Mrs. K]

What is your coop and run like for space, and the total number of birds?

 

[MAT10]

10 birds
Total sq ft...coop & Run = 104 Sq. Ft.

 

[rosemarythyme]

Do you free range at all? You're at the very minimum amount of space, and not all birds handle confinement as well as others, so boredom and confinement stress may be a factor if that's the amount of room they have to use.

 

[MAT10]

They do free range 3 - 4x a week. Her eggs have previously been great until now. What's the deal with the egg? And what would be the appropriate space for these 10 hens...
Coop?
Run area?

 

[Logar]

And what would be the appropriate space for these 10 hens...
Coop?
Run area?

The minimum space would be 40 sq feet in the coop and 100 sq feet in the run. However there is no such thing as too big as long as they are secure and safe for them.

 

[aart]

Her eggs have also had a very dark, like bloody spot on one end, consistently, when intact.

What does the inside of egg and shell look like?

 

[MAT10]

What does the inside of egg and shell look like?

Normal