It could be a problem. Did she get a peck on the head? Could she have eaten anything funny (moldy, fermented). i had a silkie that got very off balance one day, stumbling, trying to keep herself steady with her wings on the ground. Took her inside and kept her quiet, with plenty of vitamin water and scrambled eggs. She was fine the next day. i have no idea what happened.
So, i suppose my only suggestion is to bring the chicken inside in a safe place. Keep it warm and quiet. Give it water and food. Put electrolytes in the water if you have them. Then give her a chance to recover.
i'm sure others will have better suggestions. But this will get you started.