dark

Years ago I read an article about what contributes to dark more chocolate colored racks. I recently saw someone advertise it was part of their genetic line they had for sale. I think that is bologna. What I recall is that sap from a certain type of trees was rubbed on while shedding velvet. I...

Any idea what this is and how to treat it if treatment is necessary? Never saw a bulge...just the dark spot...haven't been able to get close enough to examine if it's raw, scabbed, etc. I'm thinking maybe ringworm or something, but they were wormed not long ago... Sorry for the terrible...