Although J. Mulder and O. This shape also differs from one breed to another. Therefore, the egg's form cannot indicate the sex of the chick it will produce. If it did, all the layings of a particular fowl—or of a particular breed or strain—would be of one sex. Common sense, or any familiarity with chickens, will tell you that this is not so. So there you have it: both sides of The Controversy.
But, did the breeder send female or male chicks? A four-to-six-week wait yields a definitive answer. Male Marans chicks will eventually crow; females famously lay dark-chocolate-brown eggs. Other than waiting, people rely on four strategies for sexing: feather color and patterns, venting, surgical sexing and DNA testing. Of the four options, the least reliable is feather sexing.
With most animals, it is relatively easy to determine the sex of the newborn. The male reproductive organs are located on the outside of the body and are relatively easy to see, even in newborns. This is not the case with poultry. In male birds, the reproductive organs are inside the body cavity.