I too went through a massacure 1 year ago - but with my own dog! Chickens and dogs appeared to really get along. first mistake - I left for town was away 2 hours, returned to feathers and bodies everywhere. Once a dog, your's or your neighbor's, get's the taste and "feels the fun" of the chase it's pretty much non-reversable. My surviving chickens were "emotional" for some time. I still only let them out when I'm home. Keep your hen with you inside until she is completely healed. Then reintroduce her back to the flock at night, not during the daytime. Chickens are pretty dumb at night and if the wake up to "another one" are more apt to accept it better.