Are you sure of the parentage . If you are sure it raises questions about your rooster . There should be no single combs from this cross . They could develop into a modified blade from single/pea comb combo . Also leg color as adults should not be yellow on this cross . Chick leg color may change as they grow .
Ok I had my facts wrong. The chicks were hatched by a friend, and have pea combs and blue legs. There have been three eggs from this hen and the first one was from a different roo. That chick has yellow legs and a straight comb. The roo was poor quality and was camping in the layer pen temporarily while a friend fixed up her coop.
I still wonder if a wild type (brown leghorn) crossed on blue (black) will auto sex.
Please read the first post in this thread and then tell us why you think it might auto-sex.
The Leghorn hen has gold, not silver. You will not get sex links.
The Leghorn is not barred. You will not get a black sex link.
A brown leghorn cannot be used to make a red sex link or a black sex link. She just does not have the genes.