Egg irregularities from backyard chickens are very common. The occasional strange-looking egg from a hen is to be expected. Take a picture of it, discuss it at the water cooler next day, but don't worry too much about it- the vast majority of the time they do not indicate a serious problem. In this article we'll look at the some of the most common strange eggs and their possible causes, but first we'll need to know how a hen’s reproductive system is supposed to work when firing on all cylinders.