When i gathered the two eggs that my two chickens lay every day one of them was almost white when they are supposed to be brown.This is the first time this has happened. Can someone tell me what may have caused it and what I need to do. The shells are very hard, I give them eggs shells that have been heated and dried in the oven. And I feed laying mash or pellets.They free range in my yard for about 2 hours before they go to roost. I hope the one who laid it isn't sick.