I'm curious as to what people are finding on the F2 and later crosses. Because the F1 cross is carrying one blue shell gene and one brown shell gene the eggs are green. Since these genes are at different loci (ie. are separate genes) , crossing a pair of F1s will result in:
6.25% having two of each gene
12.5% having two blue genes and one brown gene
6.25% having two blue genes and no brown gene (ie. blue eggs)
12.5% having one blue genes and two brown gene
25% having one of each gene
12.5% having one blue genes and no brown gene (ie. blue eggs)
6.25% having no blue genes and two brown genes (ie. brown eggs)
12.5% having no blue genes and one brown gene (ie. brown eggs)
6.25% having neither gene (ie. white eggs)
In summary:
18.75% with blue eggs
18.75% with brown eggs
6.25% with white eggs
56.25% with some shade of green eggs
For now, I'm sticking to F1 crosses to make sure I know what I'm getting. However, I would love to see eggs from a hen that has two of both genes.