She's definitely got something going on. She sat down hard at the end of the video.
Scratch doesn't really have any nutritional value - but it is at least calories. If you can sneak in some feed alongside it or sub it out for the scratch with the yoghurt, that would probably help things, too...
When my chicken molted she stopped eating and lost some B vitamins as a result and did the drunken walk. There probably is more going on here, as others have suggested, but popping her a B vitamin pill might help.
I'd also see if you can get her to eat some cat food or tuna for the protein if...