I’m sorry to hear about your sister’s rabbit’s stresses, and I’m glad you’re posting out of concern for her.
Intact (unspayed) female rabbits will go through false pregnancies. The most effective way to alleviate this would be to have her spayed, so she no longer experiences those hormonal-driven instincts. It can be frustrating and stressful for the rabbit, as you mention she’s making her skin raw from nesting. I have a male rabbit, so I’m unsure if spaying is a guaranteed stop, but it most definitely will reduce hormonal behaviors.
I’m not experienced with a rabbit having it multiple times, ramping up in frequency and intensity, but it sounds like your sister’s rabbit would benefit a lot from being spayed. Is this something she has considered? It is important for female rabbits, as ~80% of them will develop uterine cancer by 4 years old.
Looking at it from a different perspective, could they not all be false pregnancies, and she may be pulling out her fur due to stress? This can occur in rabbits. If her “run” is small and she’s only getting 1-2 hours in it every day, with the other 22 hours being in a cage, that can be a very stressful life for a rabbit.
Any additional information you could provide would be very helpful.
The answers provided in this discussion are for general guideline purposes only. The information is not intended to diagnose or treat your pet. Seek the advice of your veterinarian or a qualified behaviorist.