Well... here is one of the project hens to get an idea. She was 1/8 Cochin, 1/8 Silkie, 1/4 White Leghorn, 1/2 Breda Guldre. This was where we were at 4 generations into the project. We were still a long way away from where we wanted to be. It would have taken us a minimum of 10 years to complete. Most breeds out there that were developed from a single line took 3-4 decades to create.