It appears the chick is in great distress. It's showing signs of being close to death unless these episodes are bracketed by this chick behaving completely normally. In that case, it may be suffering from a temporary vitamin E deficiency which can cause neurological symptoms. It might be alleviated with vitamin E 400iu give once a day until symptoms abate.
If this chick is showing overall signs of weakness, keeping it alive is causing suffering and postponing the inevitable.