Needing help to find out what this thing is on my Sussex hen. Cane across it after I bathed her. It's right before the huge crest of feathers on her back/bum area. It's a short thick stem kinda thing with a few short small feathers growing out of it. Approx 8-10mm tall and 2mm thick. Checked it today and although she let's me touch it.. Obviously a source of annoyance as its coated heavy around it with dirt. Any ideas on what it is??