1 of my 8 week chicks is having balance issues. Using her wings to balance a lot. She seems fine otherwise. I've brought her back inside to the brooder so that she isn't competing for food and water and put a single heat lamp on. Also added chick-quick vitamins to the water (I had stopped supplementing when they went outside at 5 weeks). She has herself wedged in a corner and has no interest in food or drink. I think she is also upset about being separated. These chicks were vaccinated against Mareks and coccidiosis. Any idea what may be the problem? Any further suggestions on what to do?