In would separate her from the Wyandottes and get some company for her (chickens are gregarious birds and need company). I have kept bantams with standard breeds in the past and do not recommend it unless the standard breeds are especially gentle and docile breeds (Australorps, Orpingtons, Faverolles, etc.). Wyandottes are not typically considered an aggressive breed, but I have had some aggressive individuals among them and have seen bantams badly battered by them.
