One of my layers - a 9 month old Barred Rock - has been standing off from the others in the flock, appears a bit puffed up, and doesn't seem to want to eat. I'm not sure what is bothering her. I don't know if she's laying because she was in the coop with all the other girls until just this morning. Her vent looks normal though. She doesn't appear to have any respiratory issues. She doesn't seem to want to walk around much, or sit, although she will go outside when the other hens do. I don't know if I should be looking for anything in particular to diagnose what's wrong. She's such a sweet, gentle girl. If anyone has a suggestion, please chime in. She normally lays an egg every day, has a good diet, gets fresh water and outside exercise. I give fresh greens from my garden daily. Oyster shells. Grit. Food is fresh and not moldy. The coop and run are clean and not overcrowded. I'm baffled as to what could be wrong.