Man, I don't know what to tell you....other than intense observation and removing any peckers.
You could make a bunch of corrals out of HC to isolate the peckers....or put them all in one enclosure.
Here is the other thread:
https://www.backyardchickens.com/threads/3-week-old-chicks-feather-picking.1456005/
So you only added more clutter a couple days ago?