Thin, brittle shells

[powerlizard]

I have 6 hens and somebody (as yet unidentified) is laying eggs with very brittle shells. The other girls are laying extremely gorgeous, hard, dark brown shelled eggs, but these are very pale and thin. I get one every day. The bottom is sometimes not even formed. The membrane keeps the egg from leaking, but the shell has a small hole where it never completely formed. The birds are just over 3 years of age. Is this common? Once I identify the hen, what can be done to correct it?

 

[Doc7]

Hello, what are you feeding?

I feed all flock with oyster shell on the side. If a hen lays a brittle egg for a week or more in a row, she becomes dinner.

 

[powerlizard]

Their feed is a non-organic laying pellet from the local feed mill. I just ordered oyster shells to supplement their feed. We'll see if it helps. Thanks for the response.

 

[aart]

The birds are just over 3 years of age. Is this common? Once I identify the hen, what can be done to correct it?

What breed bird?
If all birds but one are laying 'good' eggs', it's likely the bird not the diet.
Some do need more calcium, so maybe the oyster shells will help.
She also could just have a failing shell gland due to age, pretty common with high production hybrid breeds.
How long has this been going on?