Alex, I forgot about your Splash Marans! That might be the ticket! They should have somewhat darker eggs than the cuckoos, too, shouldn't they? Oh, and the Whitmore birds won't be here until some time in March, so you have time to build another pen! Besides, I want to hold them until we can sex them, so we each get what we want.
Filumene, I would love to see some pics of those Black English Orps particularly! I've got some good quality BBS eggs ordered, and black from a different bloodline would be perfect!