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.