To check the fertility, simply break an egg in a bowl. Find the white spot on the yolk. If you do not, use a spoon to gently flip the yolk over until you find it.
If the egg is fertile, the white mark will be nearly perfectly round and in the center it will be yellow;
it will resemble a donut. If it is infertile, the white mark will not be very round, and in most cases, smaller than that of the fertile mark. If the egg is not fertile, the 'white mark' is called a "blastodisc". If the egg is fertile, the 'white mark' it is called a "blastoderm", and this means that cell division, because of fertilization, occurred. A link with more pics of fertile vs Non Eggs! https://www.backyardchickens.com/t/16008/how-to-tell-a-fertile-vs-infertile-egg-pictures
Thanks Sally. That's what I think too. This eggs was only laid yesterday. From what I have read and compared to store bought this one is very round with a definite darker center.
It is a cross between a Rhode Island Red and a Cochin. I gave my husband 4 "hens" for Christmas and to our surprise, last week we heard a cock a doodle doo!