Who long after you lost Ethel, and moved did Herriet start acting this way? That could defiantly be it, along with the stress of moving. Maybe try some brodum busters, get her brain focused on other things, and I don't know if this will help, but nesting herbs with lavender, may be nice for her...
Hmm, that is a tricky one. Maybe offer her electrolytes in her water, just in case. OD you have security cameras? Have you lost any members of the flock recently, or given anyway? Does she eat the feathers after she pulls them out? Is your feed at least 20% protein. If it isn't, maybe she is...
Can we see a picture of this hen?
This is my opinion, I don't like them, they go in the chickens nostrils and it seems like that would affect there breathing, and they can hurt the chicken badly if used incorrectly. They seem mean I feel idk having that in the nostrils would hurt! Anyway...