It seems that as the mommy hens start acting less "mommy-ish" the others get along with them much better. They just apparently are annoyed by the weird clucking and such. I did just successfully get two mommies moved back into the flock without much fuss. I've been just taking them out to mingle in the evening while everyone is free and it's been steadily getting easier and easier every time. Even the ones that were getting into bad fights are getting along better, not that they aren't still getting bullied, but it seems that somebody at least backs down now.