Oh, no!
Sorry to hear this, guys!
When we had our big BO roo, Brutus, he started going after the kids. We used Rooster Red's roo page, and it helped a lot.
What I would do is chase him down, and sometimes it took a while, but chase him down and hang him upside down. Then I'd lay him on his side on the ground, while holding his legs, and have the kids come over and pet him.
He got much better, and the kids weren't a target anymore.
And we LOVE Morgan. He's finally made all nice with the girls and is getting his daily quota.
Bertha still challenges him EVERY day, and as of yet, he's had no luck with her that I'm aware of.
I hope this all works out for you, he is indeed a gorgeous roo.
Em