I have 6 black copper marans chicks that are 2 - 3 days younger than yours. They are not nearly as developed as yours either Mine turned 3 weeks Monday, but they look more like your 2 week pictures. None have any red coloring on their combs or developing wattles yet. Maybe it is because of the hot temperatures here. I leave them outside all day and then bring them inside for the night. In the 90's last week and the 100's this week. Looking at mine right now, I see 2 that have bigger combs and they are the only two that like to chest bump, so I am hoping for 4 pullets
Michiele
Michiele