I have a chicken who is about 3 and a half months old, 1/2 Black Giant, 1/2 Americauna, and yesterday it started acting weird, standing by itself, head tucked. Last night we had a hard time getting it up on the roost, and my husband was finally able to get it into a nest. It was still in the nest at 10L30 this morning, and when I went out at 11:30, it was out of the nest, but just standing with it's head tucked, feathers kind of fluffed up. I decided to put it in a cage by itself, and went inside to mix some warm water with vitamins and antibiotics for it. When I came out, it had moved to the back of the coop, but was still standing the same. It was very easy to move, and is still standing in it's new cage the same way. Up until yesterday, this was a perfectly healthy appeary chicken. Any ideas?