eggs that feel like cardboard

[Den]

I have two chickens that share a small coop. They are 9 months old. The Red sex link started laying in June the Plymouth Rock in September, last week one of them laid 2 eggs in one day but one of the eggs was translucent and not completely formed. The next day we were an egg short, the next two days the egg shell was so thin that it cracked before we got to it, we had a day where the egg was thin shelled by ok, now today the egg feels like cardboard. The other egg is fine. Guessing by egg color I would say it is the Plymouth Rock. What is wrong???

 

[bobelot]

Not sure what's wrong but u should give them little peices of oyster shells to strengthen the shells

 

[Den in Penn]

When they lay two eggs in one day one of the eggs is usually deficient in some way, smaller or thin shelled. And they mostly skip a day after that. With the thin shells after that it sounds like a calcium problem. Since you got one that I'm assuming was thicker shelled as well as rougher than normal I guessing that she may have had a mild illness. Giving her a vitamin boost with vitamin D might help. If she returns to thins shells add a calcium supplement.