I was holding my rooster this morning and whilst looking through his feathers I noticed some very odd patches on his skin, they were circular, and a dark purple colour. They were raised from his normal skin like a volcano with some white crusty bits on it, at the top of the "volcano" there was a small white patch with white furry fluff (looked like white hairs). the whole purple patch felt pretty hard and I could actually feel one on his leg through his feathers as a hard lump. He has 3 of these (maybe more) ranging from 0.5 to 1.5 cm across. Any idea what this could be? I'll try to get some photos of them tomorrow morning