either a RIR or a white Plymouth Rock produce? When I was a kid, I did a science fair experiment involving incubating eggs, opening them at 3 day intervals to preserve in formaldehyde (yes, very unPC and day 18 was awful) and raising the rest. My father picked the breeds: leghorns (the one his family had in 3 huge barns on their farm), RIR and Plymouth Rocks. I'm not sure I had a leghorn rooster but I had hens of all 3, 2 RIR roos and 1 PR roo. I incubated some of the fertile eggs of all colord and ended up with good layers that didn't resemble their parents; it's been 40+ years since I had chickens and cannot recall if I got more roos or not.
I'm having a discussion with Bill about chickens; he totally discounts leghorns but loves Golden Comets. I know I had mutts but is there a name for what I had or might have had? I've searched for information regarding these crosses and come up empty.
My personal favorite cross that I would like to repeat in the future was Blue Andalusians x Easter Eggers. I had a black roo and a blue roo result, both with brown 'highlights', and several blue/black EE pullets the same. Gorgeous birds.