My chickens wattles and combs look black why is this?

This could be their natural colouring; hens such as a Bluebel tend to have a darker comb and wattles. However, it could be due to a lack of oxygen in their blood stream, which might indicate a possible respiratory infection, heart or lung problem. If the comb and wattles are usually red, and they have changed colour it is recommended that you take your chicken to see a veterinary professional.