Rainbow Eggs: Crossing back

[HollyParks]

Happy New Year!

I have more egg color questions. I have some beautiful layers; one of my girls is a green egger (Mother is F1 Olive Egger crossed back to a homozygous blue rooster). She lays a beautiful rich mint green egg.

I’m curious what her brother’s genetics would be. Does he carry the brown egg shell gene at all? I’m curious for when I breed him to other hens. I’m just unclear with the multigenerational projects.

Thank you!

 

[The Moonshiner]

It would be extremely rare that he wouldn't. Brown shell genes are different then the blue/white shell genes. There's said to be 13 or more brown shell genes. Idk what genes the parent carried but I'd assume at least a few. It wouldn't be easy for him to have not gotten any.

 

[NatJ]

I’m curious what her brother’s genetics would be. Does he carry the brown egg shell gene at all? I’m curious for when I breed him to other hens. I’m just unclear with the multigenerational projects.

Gene for not-blue eggshell: he may carry it or he may not. He has at least one gene for blue eggshell from his father who you say is homozygous, so the only question is whether the mother gave a blue eggshell gene or a not-blue eggshell gene.

Genes for brown on the eggshell (makes blue eggs into green eggs or white eggs into brown eggs): he almost certainly carries some of those genes. There's no easy way to predict how many of those genes he has, because there are quite a few and each one makes the brown a bit darker or lighter. It is likely that he has about as many as his sister, but he could easily have more or less.

 

[HollyParks]

Thank you both! That’s good to know! I was trying to predict what their daughters would lay. I guess it’ll be a surprise!