I have been searching the internet for 3 days. I have found NOTHING so far that can tell me what in the world is going on with my chickens. First, their faces look dirty. Like they dipped them in a dust pan and it stuck to their wattles, combs and faces. Today I found their poop looks different. It almost has a coffee grind look to it. They are acting fine, laying fine, and eating well. I put them on pellet feed about a month and a half ago. They free range and get our compost scraps every day. They are almost 6 months old. The poo is under the roost and there is a lot of it so I assume it's more than one of them. They all have the grey markings on their faces.