EEs would probably yield the widest possible assortment of colors, but many of them are pretty slim - not ideal for processing if you're hoping to get some meat.
Marans would be nice for dark eggs, BCMs having the darkest eggs (though realistically hatchery birds aren't likely to lay very dark, but they should still be a darker shade of brown).
Marans would be nice for dark eggs, BCMs having the darkest eggs (though realistically hatchery birds aren't likely to lay very dark, but they should still be a darker shade of brown).