I have 11hens total, 5 are white (unknown breed, bought from tractor supply) and 6 are rhode island reds....we have a coop with a door that goes into a run. the door is always open, the run is huge and totally fenced in so predators can't get them. the chickens always have plenty of food and water and access to it 24/7. all the hens go out together and go back in together, they just do it on their own and follow eachother...well, all but ONE. I've noticed for the past couple weeks this one white hen has stayed in the coop by herself away from the others. she hangs in this one nesting box all the time. she eats and drinks and is laying normally. but she stays in this one nesting box on top of the eggs shes laid (theres no rooster). I pick her up, move her, take her eggs, and she goes right back to the spot. a couple times my husband picked her up and put her out to try to get her to socialize with the others. she wasn't having it, she went right back to the nesting box. we've also noticed she has developed a bald spot on her belly and it's a little red. there are no parasites and none of the other hens have this...What is this? is this normal behavior for a hen? Should I be concerned? She is about 8months old. Theres been no change in food or routine. PLEASE HELP!!!