thought dark brahma are friendly birds

[nkcsweetie]

I have one dark brahma, a little over 6 weeks old and 2 red sex links, they are 5 weeks old....well I got my rsl first and decided to add another so got the brahma a little older than the others, i was told this breed is very friendly but she's picks on my rsl alot. They can't flap their wings, run, etc..without the dark brahma going after them...is this pecking order? she hasn't drawn blood or ripped feathers out yet...but just a little worried cause the other 2 are very timid around her......