What do you feed including treats?
Have you tried giving her vitamin therapy to see if it helps with her neck issue?
I would give her 400IU Vitamin E and 1/4 tablet B-Complex daily along with some scrambled egg to help with the uptake of E. Try this for at least 3 weeks and see if the vitamins make any difference.
As for the question of dust bathing - do you see her try to dust bath on her own? If you take a shovel and loosen some dirt for her, will she get in dirt and try to bath?
You mention video - the BYC upload doesn't work, you'll need to upload your video to a platform like YouTube, then provide us a link.