This red hasn't shown any changes in weight. She's the oldest red I have from my first flock so she's about four years old. She's been very listless for a week now maybe a little less. She does come out when they free range but walks very slowly and spends alot of time in or out of the pen standing isolated and puffed/kind of huddled with her tail feathers down more than normal. She does peck around some and did show some interest in scraps I threw in today. She has been roosting until tonight she was still on the floor standing in the corner when I went out to close up so I left her alone. I did pick her up today and examine her vent...no mites thankfully nor any other sign of them anywhere but sprayed her there with some natural mite killer just because it couldn't hurt. Butt is very poopy but vent is not blocked. I don't think there's any blood in her poop but it is off color and more light reddish brown from what's stuck on her butt feathers. I did notice some loose poops from one other bird the other day but the other three hens her age, the 6 younger hens, and the rooster her age are all acting normal. Recently they've been more cooped up with less room in the pen because of snow until we got some major melting in the last few days. However the coop is big enough to accomodate all of them in a pinch and they did have some room I made in the pen. I'm not really in a position to isolate her and I'd rather not if I don't have to. I think I'm just going to put some raw apple cider vinegar in their water tomorrow. Any other ideas or suggestions? Thanks in advance.