Egg Colour Change

[patbhoy]

I've had my 4 Isa Warrens since October 2009, they have always been good layers giving me at least 6 good brown eggs per week each.
My problem is this past week the quality of eggs has dropped dramatically, I have been receiving a few white shelled eggs with quite a rough surface to the shell and today there was a very small egg maybe only around the size of a 10p piece.
I went out to the coup later and had a soft shelled egg (merely a membrane), is there something wrong with my chickens and is there something i should be looking out for.
There has been no change in their food but have not been letting them free range just as much and their diet consists mainly of layers feed and a few scraps.
Its been a bit colder lately and wonder if this would have any effect on egg quality.

 

[Lesa]

Are they molting? Do they have access to oyster shell?

 

[patbhoy]

Quote:
Dont see any signs of molting and my layers feed has oyster shell in it.

 

[feathersnuggles]

Get some crushed oyster shell, from your feedstore, and offer it free-choice in a dish, where they can eat what they need, when they need it. If they are free-ranging or just eating stuff besides their layer feed, they definitely need another calcium source to balance out whatever is not their layer feed. Layer feed usually just barely has enough for average hens, if they just eat layer feed. I had the same problem: pale eggs, rough with warty calcium-deposits, and thin or soft shells. I kept their oyster shell dish filled to the top and the hen with the "problem" got better.

ETA: in the meantime (if you haven't gotten to the feedstore yet) give them an emergency dose of calcium by crushing a Tums or two in some plain, active-culture yogurt. Maybe mix in a little plain oatmeal, so they can pick it up with their beaks. The Tums and yogurt have lots of calcium, and even though it is not in the form of calcium-carbonate (which is best), that emergency dose will help get some calcium into their bodies. Once they start eating the extra oyster shell, it may take a week or two before you start seeing better eggshells.