I am new to chickens. We have 28 hens with 2 Roosters. We are going to be using eggs to eat in addition to hatching. We also want to sell some eggs for hatching. Ours our free/open range chickens so I don't really monitor who is getting fertilized. How do we separate the eggs? How can I tell which ones are which? How can I be sure to get fertilized eggs, or non?