Thin shells - hereditary?

[WaveyCreekChickens]

My chickens diet is organic layer and a bit of scratch, bits of fruit and any bugs and scraps they find. They have access to oystershells and crushed eggshells. They get a snack plate with any leftover bread or other scraps at night, that I add a little ground up oystershell to. I do believe they should have enough calcium.

My hens will be 3 years old in March. They started out laying lots of healthy looking eggs, until they were about months old. 2 of them started laying thin shelled eggs (I often found them in the morning, under their sleeping roost). Eventually one of the thin shelled layers stopped laying. (She was later taken by a hawk.) The other thin shelled layer layed fewer and fewer, and mostly thin shelled, then also stopped laying.
I believe they are sisters.
The third sister lays good eggs, regularly. She decided to hatch out a clutch of eggs (out of 5 eggs only one hatched, a hen).
The fourth hen is different looking, but likely related to them as well. She did well and layed great eggs reliably, but is now starting with the thin shelled eggs.
When the shell is so thin, they see the colour through it, peck it and eat it, or it breaks in the nest.
Now the little one is grown up and lays as well. Her eggs are good so far.
I have read the article on here about egg problems. It seems the suggested reasons for thin shelled eggs do not apply to my hens. I have a feeling they have a hereditary condition that does not let their systems use the calcium.
I am wondering if anyone here has had this problem or has heard of it.
Thanks

 

[ChickenCanoe]

Most any problem could be hereditary.
Acidifiers like ACV in the water can help them utilize more calcium.
Another thing to consider is that it isn't just about total calcium, Ca, phosphorus, vitamin D3 and magnesium need to be in correct balance.
Most feeds should have the correct ratio of those nutrients. Providing oyster shell on the side in a separate container and eliminating treats can often correct problems.

 

[aart]

Acidifiers like ACV in the water can help them utilize more calcium.

Thought it was the opposite?

 

[DellaMyDarling]

Have you ever had your source of water tested, by chance?

I have to play detective with every animal we get, because our hard well water acts as antagonist.

 

[WaveyCreekChickens]

Most any problem could be hereditary.
Acidifiers like ACV in the water can help them utilize more calcium.
Another thing to consider is that it isn't just about total calcium, Ca, phosphorus, vitamin D3 and magnesium need to be in correct balance.
Most feeds should have the correct ratio of those nutrients. Providing oyster shell on the side in a separate container and eliminating treats can often correct problems.

I will try the ACV in the water. I do it for the goats anyway.

 

[Criticalicious]

What breed of chicken and from what source (online hatchery or breeder, backyard farmer, etc.)? Egg output varies over their lifetime, depending on genetics. High production breeds for example, start having problems around age 2-3 years, sometimes have shorter lifespans, and although heritage breeds slow down at age 2, they can lay eggs for much longer, living up to 10-12 years.

 

[GC-Raptor]

Thought it was the opposite?

I googled (does ACV help hens absorb calcium?)
This from Scratch and Peck came up first. It depends on the temperature according to them. GC

 

[WaveyCreekChickens]

What breed of chicken and from what source (online hatchery or breeder, backyard farmer, etc.)? Egg output varies over their lifetime, depending on genetics. High production breeds for example, start having problems around age 2-3 years, sometimes have shorter lifespans, and although heritage breeds slow down at age 2, they can lay eggs for much longer, living up to 10-12 years.

We got our chicks in the spring of 2018.
We had planned to get 4 pullets of certain heritage breeds...
Then we visited a young boy who needed to get rid of his batch of chicks, due to weasel break-in.
We found ourselves with a flock of 9 teenage chicks, out of which 4 turned out to be hens.
The young boy called them Barnefelders and Wyandottes, but they do not look like those breeds.

So, we’re not sure of the breeds, but they started having egg shell problems after a short while of laying. They are not 2 years old yet.

 

[Criticalicious]

I normally support Scratch n Peck, but I am rather confused by that article about ACV. The first part says, ACV increases calcium absorption but then it says, the acidity inhibits calcium absorption. So which is it?

 

[GC-Raptor]

I normally support Scratch n Peck, but I am rather confused by that article about ACV. The first part says, ACV increases calcium absorption but then it says, the acidity inhibits calcium absorption. So which is it?

I know, it's confusing.
I don't use ACV, my waterers are galvanized. GC