I will have to disagree on the two sections in bold. A fertilized egg, or even a non fertilized egg for that matter, is extremely easy to see. The hen’s DNA on a non fertilized egg shows simply as a white dot.The sign that a fresh egg is fertile is often hard to see. It appears as a cloudy or a very slightly darker spot on the Yolks Surface
Once the egg is fertilized and contains the rooster’s DNA, there is a white ring around the white spot resembling a bullseye.
Adding a rooster to the flock is probably the easiest integration there is. However, it isn’t a good idea to add any bird to a flock when you won’t be there to observe. Older hens usually present more of a problem to a new “man around town.” And then again, the new rooster could possibly present a problem by being too rough on the girls. It isn’t always pretty when a cockerel begins learning, bless his heart, but you definitely don’t want one that hunts a hen down and is very aggressive in mating. But a 15 month old rooster should have already worked out the kinks and hopefully will be a gentleman as well.When do you recommend that I integrate him,