It has recently dropped in temperature here and I first noticed dark dots on one of my 6 month old hens comb yesterday. She has the largest floppiest comb. Today I noticed several of my hens have these dark dots on their combs. They don't brush off or move so am I correct to think they are not mites? Could this be a temperature thing? It has only gone down into the 20's for a low outdoor temp. They have a nice coop with lots of pine bedding to stay warm in and are protected very well from the elements. Thoughts???