The offspring will be intermediate in size and not as good in the egg production catagory. Since broodiness is multifactorial dominant you can get some birds that may or may not go broody. It would depend on the genetic of the Giants. Two non broody lines can be crossed and produce broody birds because there seems to be more than one defective gene that blocks broodiness. Do they have a high incidence of blue butt.
Blue butt is when a patch of black melanin forms in the abdominal region.
You can see it through the skin around the belly button and sometimes it extends all the way to the anus. Ron, Thanks for your response. I only dressed out the males, but I didn't notice blue butt if it existed. I kept one roo because he was so handsome. Production birds won't molt in mid year they have been selected to delay molt for a long time and usually won't molt for 18 months, but Giants may molt on a more normal schedule following the change in day length.