Have you ever had a bird that suffered from twirling? I am wondering what it looks like at the onset??? Oh Lisa...I will be devastated if she has it...it is a horrible neurological disorder and she will need to be euthanized.
I've had birds that have exhibited signs of neurological disfunction in new homes but as I said, it's always immediately stopped when I rehomed the bird to a new environment. I had a yellow hen that I put into the aviary, she was fine the first few days but then got obsessed with going back and forth between the swing and wall. When other birds landed on the top of the swing, it seemed to be what set her off. She seemed like she was suffering from extreme vertigo. Although it upset my plans, I moved her to a smaller temporary cage and she immediately stopped all strange behavior. I later moved her into a breeding cage with a mate and she has been fine ever since.
I also had a new bird that I recently got that was doing back bends in his quarantine cage. I realized there was a hanging lamp right above him and maybe it was freaking him out. I moved him to a different room away from the overhead lamp/lights and his behavior immediately stopped. Now he's in my aviary and he's always been fine.
I have no doubt that if I had kept either bird in the same scenario, they would have continued to deteriorate. I find that gouldians especially seem more than likely to adopt this sort of behavior when anything is above them. I have close to 40 gouldians and have seen this behavior about 4 times - 3 times with gouldians (all were cleared up with a change of cage/location), and once with green singers when I moved them to the bottom tier - I ended up adding foliage to the top of the cage and that seemed to curb the behavior in them rather quickly.