In the attached photo the first egg is from my White Leghorn, the 2nd is from Rhode Island Red, the 3rd from Buff Orpington, the 4th from Speckled Sussex and the 5th from my Barred Rock. All five hens are from 1 to 2 years of age, and although the Leghorn is a bit on the lean side, all the others are full bodied and very healthy. They are all quite compatible and get along extraordinarily well. And they all share the same nutritious pellets. So why is the Barred Rock's egg so much smaller than the other eggs?