Experts said a 4.1-ounce egg laid by an Iowa chicken is unusual, but not without precedent. Nathan Batten said Aussie, a black Australorp chicken, laid the egg measuring 3 1/2-inches long and 6 1/2 inches in circumference at his farm near Bonaparte February 18th. The egg weighs about twice as much as an egg labeled large by U.S. Department of Agriculture standards and exceeds the average 2 1/2 ounces for a jumbo egg. Sean Skeehan, who raises chickens at Blue Gate Farm in Chariton, said egg size is dictated by breed, not by diet. He said the huge egg was not surprising given previous 3-ounce eggs laid by Aussie. Batten said he is planning to contact Guinness World Records to determine whether the egg was a record-setter.