I would think eventually you would want to keep a Ayam Cemani rooster for breeding purposes as Cemanis are so valuable, however if you're just wanting a rooster in the meanwhile to rule the roost, I would suggest getting a Barred Rock rooster. They are readily available, inexpensive, and tough...
Welcome to BYC. Glad you decided to join our flock. A bigger cockerel might solve your problem, but if you do get a bigger cockerel I would remove the smaller cockerel from the flock; not only because the bigger cockerel will abuse him, but also because you are already straining the rooster to...