Hey there:  I hope someone here can help me because I don't have a clue what this could be.  We have 12 Buff Orpington hens.  They are 5 months old, and some are just beginning to lay.  About half of them have developed black crusty spot at the base of their beak.  One also has a small black spot on her comb, and one has a black spot on the bottom of her ear.  They seem to be acting normal; eating and drinking.  It has been extremely hot and humid here in Southern Alabama.  They are free rangers.  Picture attached.