End of egg has lots of calcium deposits and very thin

[Ccort]

I have one girl who is now consistently laying a much lighter colored egg than she used to and one end is always covered in little white bumps. That end of the eggs can be anywhere from paper thin to a thin shell. Her eggs are almost white in color and they used to be tan.
What might be going on here? She is on All Flock feed because I have one who is spayed so shouldn't be on layer feed. They have constant access to oyster shell.

 

[azygous]

This is common among aging layers. How old is your hen?

 

[Ccort]

This is common among aging layers. How old is your hen?

She's only a year old

 

[azygous]

Then this isn't normal. Has she had any respiratory symptoms lately? What breed is she? Has she lost any weight? What is she fed?

 

[Ccort]

Then this isn't normal. Has she had any respiratory symptoms lately? What breed is she? Has she lost any weight? What is she fed?

She's a brahma. She hasn't lost weight and isn't having breathing issues. She's fes Purina Flock Raiser but as of yesterday I switched them to Nutrena Naturewise All Flock. I have another thread going though because I have lost three chickens within six months suddenly and trying to figure out what is going on!

 

[azygous]

The other thread may have information for this issue. Could you like to it? Describe the symptoms of those chickens before they died.

 

[Ccort]

The other thread may have information for this issue. Could you like to it? Describe the symptoms of those chickens before they died.

https://www.backyardchickens.com/threads/a-hen-dying-every-two-weeks.1579560/

And

https://www.backyardchickens.com/threads/fatty-liver-disease.1578234/