Two year old hen, Barred Rock, is acting a little unsteady today. She occasionally shakes her head. When she walks, it resembles someone who has had one drink too many. I have four others who are acting normally, although several are molting in various stages, this one included. She seems to be eating and drinking normally. I feed Purina layena pellets so assume vitamins are o.k. I also allow them to free range several days a week. Read forums suggesting possibly Vitamin B deficiency or even Marek's disease. I have never treated for worms or mites and have never observed problems (although I will admit I'm certainly no expert!) Anyone have any advice for me to follow? I was going to purchase some baby vitamins and try that but any help is very appreciated. Thanks.