Something Wrong With My Hen

I have an almost year old buttercup hen who's normally super energetic and noisy. She usually chirps and makes noises constantly, and she doesn't like to be held for more than a few moments. We always let them out for a few hours each day in our backyard. A few days ago, when we let her and the other hen out, she was fluffed up a bit, and walked slowly. She wasn't making nearly as much noise as usual, didn't run to get treats (she slowly walked over, instead). She's still eating her food. It's rained at least once a week for the last few weeks, and she's started laying less, if that has anything to do with it... She was fine the next day, and for a few days after that, but she's acting like that again today. I have no idea what's causing this, whether it's the colder weather, something she maybe ate... We recently bought some chicken vitamins and a new brand of oyster shell things but I don't think that's it... So any advice would really be appreciated.

I have a few questions that might help us to work out what may be troubling your girl:

What does her poop look like (normal / runny / green / is there any blood in it?) Have you wormed your birds recently, and if so what did you use?

When you listen to her breathing can you hear any 'rattling' or 'clicking'? (If there is any it will be more noticeable if you pick her up and she isn't happy about it, rather than if you listen to her on the perch at night, when she is calm and quiet.)

Is there anything else different about her - swollen face, puffy or partly closed eye, limping?

What has the weather been like on the days she is hunched up?

Have there been any recent changes to your setup at all? For example a new type of bedding, another bird introduced (although from your post I believe that you only have two hens?)

If you think of anything else that might be relevant then please let us know. It is very difficult to 'diagnose' a problem or illness online, and a hunched up bird could be suffering from anything from coccidiosis to respiratory infection. The more information we have the more we might be able to point you in the right direction to help your girl.

Her poop is solid green with sort of white liquid also, I just noticed that it wasn't normal. I have no idea what that means though. Her breathing is normal, and we haven't wormed them or changed the coop at all. I'm not really sure what else to say. Right now I'm outside with her on my lap. She seems a little more talkative and attentive now that she's warm? I'm not sure if that has anything to do with it. It's rained a lot the past week, and we usually don't get much more than a little bit of rain for less than hour, which is a big difference. Because of that it's been colder, also

we actually just brought her inside for an hour and a half and gave her lots of warm water and food and she seems a lot better, and we're going to try turning the light on for them inside the coop tonight.

Bringing them inside getting them warmed up sometimes helps. She may just need some more attention getting enough to eat and drink in case she is not getting her share. That should help her deal with the cold. I usually put a heat lamp on in my coop when it gets down to 15F.