If you're saying that you gave the castor oil/turpentine mixture down the esophagus to flush the worms/larva/eggs after treating with levamisol...I agree.
Some folks have used a feather dipped in kerosene and inserted the feather deep in the trachea to kill the gapeworms.
Your pullet may have gapeworm. I HIGHLY recommend that you take a fresh fecal sample from her to a vet's office and get it checked for gapeworm eggs and/or any other types of worm eggs. They'll be able to tell you what type(s) of eggs are present on the microscopic slide. It shouldnt cost much...