We have 3 Buff Orphingtons about 2 years old. Recently got 4 new chicks of various breeds that we have had separated for about 8-10 weeks. Just introduced them into the coup on late last week. Everything was going fine but over the past two days one of our older chickens has become lethargic. Sitting around mostly - she isn't broody because she does move around but just a few steps and then sits back down. Not sure if she is laying - we are getting about 2 eggs a day which is typical from the three of them. Today I separated her from the others. I gave her a warm bath in case she has a egg stuck. Underneath her vent does seem swollen and it looks like she is pushing but there is no redness of the skin and the area underneath the vent feels soft. I don't see any clear evidence of mites although I have to admit I'm not exactly sure what I'm looking for. Her neck feels fine. She has been having green poops this afternoon. I've put her in a separate cage w water, food, and some rice with yogurt. Anybody with thoughts? I've read a ton of posts and have tried to do what they say but not sure if anyone has other thoughts. Thanks.