I would recommend for your paint pen, do not put in your black hen if the roo covering this pen is black. it will only confuse who has the paint gene when they hatch. if your unsexed chick turns out to be a cockeral, then use him on your solids, black or white. i just hatched out 10 chicks yesterday 6 spotted and 4 solid blue/black. i know these solids all can carry paint but if I had a solid black roo in there as well, i'd never know.I hope to set up a paint pen in the spring I have one paint pullet and just hatched a paint chick sex unknown at this point. I was thinking of including my black roo a black hen the paint pullet the chick I also have a white hen and cockerel not sure if I should include the white birds or not.