Could be a lot of things. My first thought would be to rule out pain/itching - from mange or anything else. But because it's triggered by going in the crate, I wonder if it might be more of a frustration behavior, something developed while confined and unable to entertain herself or have an outlet for any anxieties. This can happen sometimes in neglect cases, but also in dogs who are in the shelter for a while and have trouble coping with that stressful environment. If that's the case, it may even have started as an itch/pain but now it's just become a habit.
There are dogs who tail chase compulsively, and it seems to have a significant neurological/genetic component, but I doubt that's what's happening here. It's rare outside of the affected breeds (Bull Terrier and German Shepherd are the big ones), and not even super common in those breeds. So I'd assume it's an attempt to relieve discomfort and/or learned stress response.
I haven't read too much about treating these kinds of behaviors in dogs, but making sure she has stress-relieving alternatives like chew toys (esp. ones stuffed with goodies, just make sure to calculate it into her daily calorie intake) and lots of good enrichment and mental stimulation will help any dog's quality of life!
There are dogs who tail chase compulsively, and it seems to have a significant neurological/genetic component, but I doubt that's what's happening here. It's rare outside of the affected breeds (Bull Terrier and German Shepherd are the big ones), and not even super common in those breeds. So I'd assume it's an attempt to relieve discomfort and/or learned stress response.
I haven't read too much about treating these kinds of behaviors in dogs, but making sure she has stress-relieving alternatives like chew toys (esp. ones stuffed with goodies, just make sure to calculate it into her daily calorie intake) and lots of good enrichment and mental stimulation will help any dog's quality of life!
