One of our chickens is about a year old and has been losing feathers for about a week or so now (they're all over the garden). Yesterday I noticed she was hiding under a bush. I coaxed her out and she was very unsteady on her feet - trouble walking and would fall over. As she goes to eat, she falls forward. She is also sleeping on the floor rather than roosting like she normally does. We've also noticed we're getting one less egg each day, but the symptoms don't seem to mean she's egg bound. Today she's the same. Anyone have any ideas?