How can you tell which one is the bully? We have 21 chickens. Only 2 are being pecked.
Lots of observation! My one hen that was being bullied was especially afraid of a certain other hen and would run like crazy and hide in the house whenever that hen came around. However, it could be that your two are being picked on a little by everyone, or several, in which case, probably the best bet would be to put them in a pen of their own within the big pen so that they can't be pecked but can still see the others. Then re-introduce them again. It took mine about a week or two and she's still low on the pecking order but no serious bullying anymore.