I have a black copper marans hen who has a poopy butt. Her vent looks OK, but the (formerly pretty and fluffy) feathers under it had a big poop rock in it. I got a wet rag and soaked it and cleaned it as best I could. However, this same hen has not been laying since early December. All the other chickens in the flock have laid during this time; we have added supplemental light because our coop is on the shady side of the house, under the deck, and I'm in Colorado where there's been snow on the ground since November or so, so they have to spend a lot of time in the coop. Other than the poopy bottom and not laying, this hen looks and acts totally happy and healthy. She eats normally and runs around acting normal. Should I be concerned? Thanks in advance for any tips.