My kids have been selling the extra eggs and a customer told me there was blood in a few. I figured it was just a blood/meat dot and can be removed. But yesterday I encountered 5 eggs out of a dozen that when opened were messes. The yolk was not formed - runny not round. The white was milky color, and there was blood on the yolk or all in the shell around the membrane. What would cause this? Do I need to worry about a illness, or could this be just human error - kids picking up developing eggs from a brooder's nest? I have an assortment of 20 hens and a rooster. Occasionally we do allow a hen to hatch, but we usually keep a good eye so we don't mix. We pick up daily or more often otherwise. It has also been very hot here 90 to 110. Any suggestions would be welcomed.