Just call it a mix or come up with your own name, back then chicken breed wasnt as many as nowadays. I have a big book about a chicken breed it was a bit old, some of the breed mentioned in this web wasn't there, not to mention the unrecognized breed on the rural or secluded place, so the newest book probably even bigger.
I want to pet chicken for fun not to become a chicken taxonomist, but well, if you are a fellow pure breed fan.
Well, it looks like you can come up with your own breed if your chicken have a distict characteristic, popular among people and gain a recognition, but it need some fortune and a bit, i mean lot of time. So i wont try or mind it that much.
Or you can upgrade your tools, become a genetict scientis and make a hybrid, then you need to wait, the next day people will group up and bring no GMO sign all over your place.
Ehm..,sorry i got carried away.