Gentle pecking (with the odd hard peck that doesn't draw blood) is expected. In chicken language your hen told that chick, you're lower on the totem pole kid! Each of your older birds will do this to each of the chicks, more often during this 'honeymoon' phase, and less often as time goes on and the chicks mature. Absolutely nothing to worry about, provided that nobody is being outright bullied and blood is not drawn. IF someone is injured to the point of bleeding, remove THAT chick, (isolating them in their normal 'look don't touch' area that you brooded them in and treat them for their wound, apply blu-kote in any color EXCEPT RED, and allow the wound to scab over, without any bleeding (a couple days) and let them back in with the big birds. Chickens will be chickens and establishing pecking order while your babies are still young is MUCH easier on all concerned.
