My Americana, a 8 months old hen has been a good hen, laying averaging 6 eggs a week. Her eggs however has lots of 'bumps' on it. My another americana, laid smooth green eggs. They are pasture raised, i consider them eating very well, organic chicken feeds, i add yogurt, sunflower seeds, fruits in their diet. They are very happy chickens. Today, one of my hen continued to lay her bumpy blue egg in the morning, later evening, we found a very soft shell egg in the laying box. The shell is so thin it breaks when we pick it up. Can anyone explain to me what happened and is this something i should be worried about?