Can you create your own breed?

[BlueTheBrahma]

Producing a fair few barnyard mixes has resulted in patterns and features I’ve never seen in pure breeds. This has me wondering if I could breed these mixes to produce a new gene pool from which I can selectively breed down to a ‘breed’ which breeds true. Is this viable, and when do I cross the line between ‘crossbreed’ and a new ‘breed’? I’m not expecting it to become recognised any time soon, but just wondered if anyone understands the technicalities.
I used to have a cockerel called Barry, but gave him away as I only had a single flock then with another rooster. He was a white Brahma cross Lohmann brown and had such a personality. Looking back, I wish I had kept him because I’d have liked to see the result of breeding him to other birds to pass in both laying ability and large size. I have his sister and nephew (who is crossed again to a Welsummer) and hope to breed from them as well as crossing my Brahmas to more hybrids. Does this sound like a good idea or is crossing mixes not with my time?
Thanks.

Barry (don’t have anymore)

Barry’s sister

Freddy (Barry’s sister cross Silver Duckwing Welsummer)

 

[cubalaya]

with all the rare breeds that need work and breeders, why would you? most likely mutts and never getting to a place where they reproduce true. with that being said, i have