I'm new to chickens, so I really don't know what I'm dealing with here! One of my hens has almost ALWAYS had a bare chest (since I got her in May). I thought she was broody, for a while, but that's not the case, nor does she appear to have mites. Recently, however, her chest has become red and inflamed. I also noticed her foot was a tiny bit swollen and today pulled this out of the center of her foot, leaving a crater in her pad. It didn't feel like a scab-- it had the feel of a rock or something else worn down in there. I was shocked when it left a freaking HOLE in her foot pad! It seems like it was something similar to a hardened blackhead? I have some Tylan I could give her, but anyone know what's going on? I don't want to dose her without knowing. She's my best layer, so I want her to be healthy!