Hi, my three hybrid hens and white orp have all developed black spots on their wattles and cones. Like little splatts of tar/oil.
This has only developed over the past 2 weeks the hens are laying as normal and they all seem their usual cheeky selves.
What could it be and should I be concerned?

This has only developed over the past 2 weeks the hens are laying as normal and they all seem their usual cheeky selves.
What could it be and should I be concerned?