With all due respect, the best answer I can provide is - DON'T DO IT!Hello, Iowa Blue peoples.
I'm limited on chicken breeds I have available, for Iowa Blue breeding, & would like to start sometime.
Here's a chick that I hatched awhile ago, the cross I used was Buff Orpington/Barred Rock X Rhode Island Red.View attachment 1914766
View attachment 1914768 Here's the same chick at 3-4 weeks of age.View attachment 1914769 View attachment 1914771 Will get updated pictures tomorrow, supposed to rain all day today. Chick is 7 - 8 & half weeks old now.
Why would you want to take a rare and desired breed and make mutts out of the offspring?
Work with what you have and acquire more Iowa Blues when the opportunity arises.
I think Sandhill Preservation has them.
IMHO, none of the resulting birds can legitimately be called Iowa Blues.