Typically, if your true blue are truly laying blue; and your true green, are truly laying green, this is what you will see:
A blue (line) roo over a blue (laying) hen will produce daughters who lay blue eggs almost 100% (unless some other genetics are hidden underlying)
A mix of either green roo over blue hen, or blue roo over green hen, can vary results, but generally I find that my green tends to stick around as it took me several generations of lighter green breedback to Cream Legbar line to get almost back to what I would call a blue egg. Therefore I predict that a mix between blue and green will result generally result in green. Why is to understand the genetics.
Blue is the oocyean gene that causes bile to be thrown back into the calcite gland. It produces blue colored shells. Open a blue egg and it is blue inside and outside.
Brown is covered by 13 genetics and is a hemoglobin wash over the shell. Open the shell of a brown egg, and you see white shell inside. Brown wash over white shell, shades of brown. Brown wash over blue shell shades of green. How deep of brown (or olive) depends on how many of those 13 genes were captured in the next generation.
Since some of those brown genes tend to stick around producing some shade of green, again, I find green tends to stick around while my dark browns and dark olive greens tend to fade out. (You have to refresh the brown periodically with a true dark brown line).
My thoughts.
LofMc
