I walked out to check on the chickens a few weeks ago, and found this:This is Judy. This is not what her rear normally looks like.
My first suspicion was a blocked egg vent. Sometimes, an egg can get backed up in there, and it causes swelling (which can then lead to the feathers falling out). I had not yet encountered this, but knew that it can be fatal for a chicken. After consulting the Backyard Chicken forum, I determined that while it could be any number of things, a blocked vent was the most urgent, and we would treat it as such.
The first suggestion from the forum was to see if you could feel the egg. I decided it was in the best interest of my marriage if I completed the examination, but after violating my chicken for a couple minutes, I had to confess that I really had no idea what I was touching. I called a vet, who told me I could pay him $55 to look at my chicken, after which I asked if he knew any good butchers.
The forum also suggested treatment, the first option involved lubing up your finger and digging the egg out. That's not really my style, so I opted for the chicken hot tub method, which involves soaking your chicken's butt in hot water every couple of hours in an effort to loosen her muscles and help her drop the egg. We moved Judy into the house and put her in the dog kennel under the heat lamp for the night, and Buster thought he was getting a super fun family sleepover. In the meantime, I posted a photo of her butt on the BYC forum, hoping a more seasoned chicken owner might give me a better idea of what's up with her butt.
The next morning, we woke early to bathe her bum, and while Mitch was holding Judy in the basin, he suggested I check the forum to see if anyone had responded. Turns out, chicken butts always look like that, and another chicken is just plucking her feathers out. Turns out that chicken is Angie, as I noted that the rest of the chickens (except for Angie) are missing a few feathers as well. Only took them a year, but I guess the pecking order has finally been established. At least Judy got a spa weekend out of the deal.