Hens laying very thin shelled eggs

[AmyZ]

Hi new to chickens but have four Hyline hens. Two (purchase in Aug) lay beautiful eggs. The other two (purchased Feb at 18 weeks old) lay eggs with shells either broken (or usually break picking up) or are just membranes. The eggs have been like this since just after I bought them.

Their feathers look a bit duller than the two 'good' chickens. But they otherwise look very healthy.
I feed them high quality food and have tried different types.
There were allowed to free range, but have kept them cooped up for the last month to see if this would help. It hasn't.
They have free access to poultry grit.
They lay almost every day.

I would LOVE any advice on what to do. I am sick of cleaning messes out of the chicken house!

Thanks so much for reading!

P.S. I'm sorry if this is in the wrong category. I wasn't sure if it due to disease or nutrition!

 

[Pork Pie]

Hi and welcome to BYC - thanks for joining us. This link may help - https://www.backyardchickens.com/a/common-egg-quality-problems . I'm sure others will be along during the course of the day to give advice.

Best wishes
CT

 

[ChickNanny13]

Are you feeding Layer? Do they have access to Oyster Shells?
You mentioned Grit but not Oyster Shells which is a supplement to strengthen egg shells.

 

[AmyZ]

Thanks very much CTKen! I hadn't seen this page.
Given the long time, it looks like it is either nutrition (although I'm not sure what else I can do!) or disease.
If disease, I can't see anything obvious. I will consult with vet on how to treat possible internal parasites.
Thanks again!

 

[AmyZ]

ChickNanny123, yes I'm feeding Layer Crush (good quality recommended by breeder) and they have unlimited access to oystershells.

Thanks for your interest

 

[AmyZ]

Sorry, I meant Oyster shells, not grit.

 

[ChickNanny13]

Have you called to ask the breeder for help? Will be following to see if this issue gets resolved.