My hen has been getting crusty butt feathers lately. The first time (when I got her) her whole butt had poop all over it, and looked like vent gleet but without the redness and foul smell, discharge, etc. We gave her a warm bath with Dawn dish soap and she was fine. Has a nice, fluffy butt. This was last week. Today I noticed the problem is reappearing. She has normal poop (weird I know), always a healthy crop, no redness around the vent, no lice or mites, and lays clean eggs daily. Something just isn't adding up. All of my other chickens are perfectly fine. Any idea what's happening? It's stumping me. She's a very healthy bird otherwise.