Fragile eggs

Hi everyone,
I wonder if anybody can shed some light on why my chicken has been laying such fragile eggs?
This started 6 months ago now and this one chicken (Creepy) has been consistently laying thin-shelled eggs nearly every day. Sometimes they break on laying, sometimes I manage to get to them and rescue the perfectly good egg inside. Usually they get eaten and make a mess of the nestbox bedding. I have read endless forum posts on this which normally say, needs more calcium OR cull the bird!
Here she is; she is about 2 and a half, a feisty, some might say aggressive, bird. She is chicken #2 in the pecking order of a flock of four and is not going to be culled. She is our favourite chicken (don't tell the others).
She has only recently grown a full set of lovely, fluffy feathers on her back-side, having been bald down below since she came from the chicken farm in August 2011. She once had an impacted crop about 10 months ago, cured with the fresh pineapple treatment, otherwise healthy as anything. There were some redmite in the coop; under control now, just a few around.
They get layers pellets and ad lib crushed eggshells/poultry grit as well as cracked corn porridge with yoghurt and loads of greens. The other three chickens' eggshells are rock hard; sometimes difficult to crack, so I am sure there is no dietary deficiency. They get extra cod-liver oil as well; I thought it might be lack of daylight causing problems with vitamin D production and therefore calcium absorption, but this has been going on for too long now.


This pic shows Creepy chicken's eggshell on the left, compared with another one's shell; you can see daylight through it as there is a very thin layer of calcium.


This is the shell backlit - there is quite a bit of pigment in them usually, brown freckles.


And this is it taken with flash to light the inside. It's not that abnormal but it is annoying to lose an egg every day and it makes a nasty mess in the nest box.
Anyone know what might cause this and whether it might be treatable? I'm thinking she might have a genetic problem with her shell gland and this is it forever. Would be great to have a way of getting her back on track.
Thanks ever so much for your help,
Love the BYC site,
Nestleaver1

 

Thank you for getting back! Those are all the same thoughts I had...They do get a separate hopper of poultry grit which says it contains oyster shell. I even collected cuttlefish bones from the beach and crushed them up (and I tasted them to make sure they weren't too salty!!).
I did just have a brainwave tho. They have had no change in offered diet BUT we did introduce a new feeder about 6 months ago; a treadle so they couldn't kick the feeder over and bury it. It is possible she just doesn't like using the treadle feeder and is not getting as much standard feed as she should? I've seen her use it but she is a stubborn one and might avoid it if she can. I will try putting the old feeder back in and see if she takes more from that.
This is the same chicken as my avatar picture; that's when we first got her so she has improved a lot.
Thanks for your help,
Cheers, Kate

 

Hi all,
So that is a good few weeks that Creepy has been offered her feed in the old feeder (just a plastic bell) in case she wasn't eating as much from the treadle, but no difference. She still lays nearly every day, always fragile so they either break on laying or she can easily break them to eat the contents.
There is eggshell available and loads of grit with oyster shell; pelleted layers' feed is 4% calcium. She is always active, alert and usually harrassing somebody so I don't suspect any general health issues.
Any suggestions on how to resolve fragile eggs gratefully received.
Thanks for your help,
Kate
P.S. Please see post on impacted crop treated with pineapple/papaya/kiwi - this needs to be publicised to save chickens from death or surgery! KT