We got 5 chickens and a rooster in April. One chicken (2 year old) Would lay thin shelled eggs and stopped laying not too long after. She seems healthy and we didn't worry about it. About 2 months later another stopped laying (1 year old)... 3 months later another stopped (2 year old). Out of the 5 only 2 were laying getting 1-2 eggs daily. The 4th (1year old) is now molting and has been keeping to herself. She has laid 2 eggs without shells. So out of 5... only 1 is laying good solid eggs. We give them egg laying food, provide oyster shells and scratch. We are in central Texas and thought the Texas heat may be stressing them out and they survived a minor flood in sept. where the coop had several inches of water. They were moved to higher ground until the water went down. We were given 5 more chickens (6 months old now) in October. All 10 seem healthy except for the molting chicken. I keep telling my dad not to worry. We will see what spring will bring but we can't help but worry about the new ones. Is it stress? Illness? We just don't know.