I have noticed for some time now that my eggs look like they have been fertilized, but I thought all I had was hens. I noticed today that I have one that has spurs however, I have never heard any crowing. My birds for the most part are black Australorps. Do roosters always crow? This one really does not look much different than the others other than the spurs. I have seen some activity that would be consistent with one being a rooster. I also have 7 guineas one of them is a rooster. I have only had chickens for a couple years and have never studied them. The youngest birds are just one year old.