Creating a new breed would require years and years of research and selection. You can't just hybrid two species together and call it a new breed. 
For starters, the hybrid would likely be infertile, as others have said. You wouldn't be able to produce anymore generations. Additionally, most hybrid animals have a lot of health issues that make them difficult to keep, and many die far younger than they would if they weren't hybrids.
If you wanted to create a new breed, you would first need to spend several years researching chicken genetics and understanding what exactly you're trying to produce, and what genes affect that.
You would need to keep hundreds of chickens over the course of probably 10+ years, and cull (kill) most of them, to even get close to a new breed.
As someone who's in the planning phase for a new breed, I'd definitely recommend getting your flock back to 100%, and doing research in the meantime. After your flock is no longer in the red, and you've got a good understanding of chicken genetics, THEN you can revisit your idea of a new breed and start making actual plans based on the knowledge you've gained.
Until then, focus on the birds you already have and make sure they're healthy and happy before considering adding new birds into the mix