I have a rhode island red hen who is about 18 months old and has been walking a little stiff legged (a little like a penguin) for the past couple days. She also has been pooping a little green-yellow and has been getting pecked by some of my other chickens-no marks being left though. She doesn't seem to want to move (walker or fly) much, she just stands in one place or stays sitting on the roost during the day (they free range all day so she and maybe one other are the only ones in the roost during the day. I am not sure what is wrong with her. She seems healthy otherwise, and actually seems a little bigger than my other rhode island reds so I am not sure if she is swelling up or just eating good. The strange thing is that she let me pick her right up, which many of my RIR's do not do. When I set her down in the yard to free range, she just stands there, eating the grass around her. I did treat my birds with some duramycin antibiotic last week for respiratory issues but it didn't seem to help any of them. Could this be related or does it sound like maybe she is sick, egg bound? I have not noticed her trying to lay in the nesting boxes. Any ideas?