This sounds a lot like my chicken. After 5 days of her suffering we finally put her Dow because she had no improvement and had almost stopped eating. I also have a video posted. Does it look like the same issues you are having?
https://www.backyardchickens.com/t/740995/please-help-with-video#post_10394223
https://www.backyardchickens.com/t/740995/please-help-with-video#post_10394223