When I went to ride my horse today I noticed little bugs all over my horse's body. They looked like specks of dirt until you look closer and see that they are moving a little. They may have been there for a long time because I am recovering for an injury so my horses have been blanketed for almost 2 months without a whole lot of attention to grooming. He has 2 small bald spots (a little bigger then the size of a quarter) on each of his sides in the same place. At first I thought they were rain rot (which would have been weird cause he's been blanketed) but now I think they might be related to the bugs. He also seemed unusually sapped of energy when I rode him, although that may or may not be related to the bugs. They might be on my other horse but I'm not sure because she is rose grey and it would be nearly impossible to see them on her coloring.
Does anybody have a guess at what these might be? And if you do, how do you treat it?