For about a week and a half this one hen has been acting strange. I first noticed she was very dirty. I have a group of hens that has taken to roosting in a tree next to our coop. This sick hen was getting pooped on. I also noticed her vent area was a mess of matted poop. I brought her inside and bathed her. Within a few days she was back to this. She stays away from the rest of the flock, seems to eat last, and kind of sulks around but I think this is more than a bottom of the pecking order issue. I have had her quarantined for two days now and she seems the same, no decline. All I had was hygromyacin in pellet form so I dissolved a few in a waterer. I also gave her apple cider vinegar in the waterer. When I picked her up to cage her she seemed really bony. She does have watery poops and she is not laying eggs. She eats and drinks very well. Could it be worms? Why does no other chicken in my flock show any signs of illness? I disinfected all the waterers with peroxide and scrubbed them and soaked them in peroxide for 20 minutes. I put about half a teaspoon of tea tree oil in the large waterers too. I have 13, 6 week old chicks right now, 21 hens and 9 ducks. I can't have an outbreak of some sort. I I have about an acre so I'm not too cramped for my flock size. I just need to know his to help this hen and keep illness from spreading. Any help is greatly appreciated. So few people I know have knowledge about birds. Thank you!