[hillary1]

we have had 3 chickens for 2 years and have recently got 3 more from a friend which are about the same age. we have had them about a week and they seemed to be settling in ok but now one of the original chickens has started to attack one of the new ones quite badlly! Any advise please?   

[Brambles]

I had a girl that was a total bully, she picked on one of her "flat-mates" and pulled all her feathers out around her rear end and breast.... I tried EVERYTHING that I knew, but she still pulled the feathers out and ate them.   Finally I separated her from the others, she has been totally happy living next door and she LOVES having all her food and treats all to herself... I think that was her problem, she was a rescue hen from a barn where she had to fight for survival, now she is on her own, she is very happy and contented.

[joyfull]

You could try spraying her with purple spray to hide the redness, or an anti peck spray or if this doesn't work then try ukadex - brown fowl smelling stuff. If all this fails then fit a beak clip to the bossy one - she will still be able to eat and drink but cannot grasp feathers.
Sometimes chickens eat feathers for some extra protein - so it could depend on the feed you are giving them although in this instance I suspect it is merely a pecking order dispute and sadly one has to be at the bottom.
If after another week of trying the above and you still have problems then remove the bully for a while - by doing this she may lose her place in the hierarchy and it gives the bullied one chance to get established in the gang