Dear BYC, I love your forum. As a first-year chicken keeper, I have turned to your site many many times to find answers. However, this morning when I found a strange bump/protrusion on my Hen's back, I found no information in your forums. I looked at your anatomy diagram and it did not help. It was on another chicken website called Chicken Eggspert, that I found the answer to my question. I learned that the little finger-like protrusion on her back is normal - it's a Preening Gland. I think every chicken owner should know this before they cut it off or something, thinking it's an ingrown feather! (... which is what I was about to do.) Please include this anatomical feature in your Chicken Anatomy Info pages. I'm going to post in the Diseases/Emergencies forum.