Probably she suffered an injury to her cervical column, nerves were damaged and she probably won't be able to walk again. However, if it hasn't been very long since the attack, the never connections could heal with the help of vitamin B-complex. It can't hurt.
Symptoms of hypothermia are weakness, drunken gait, wobbly balance, and lethargy. The symptoms you describe point to a congenital brain disorder or toxic poisoning. If you can rule out exposure to insecticide or moldy feed, I would guess genetic causes.