You could seperate them. You also could provide more entertainment.Tape a few empty toilet tissue rolls together, place a few fallen tree branches on the floor of their pen. You could even dig a small patch of grass, dirt & all and place that on the floor of their pen. make a small pile of clean sand at one end of the pen. Think "PLAYGROUND" , and give those young-uns a lot of adventures! Even an old stuffed toy will be enjoyed. they will curl up against the body, just as if it was MOM!
I read somewhere that if you only have one or two of a breed that look significantly different from the rest of the flock, it will get picked on more. It's not so much a "mean" thing....they are just trying to "fix" they're flock mate. After all, there MUST be something wrong with that gal's head, right? I hope you figure things out