We separated them. The bigger chick stopped pecking at them (but would still occasionally charge and scare the littles) after I sat there and would hold her down to the ground when she’d go after them. I have a baby monitor in the cage to keep an eye on them without them knowing I am so I could see how the big chick acted without knowing she was going to get held down if she acted up. I still wasn’t comfortable because of how small they are and we separated them again. Maybe a couple supervised play dates before fully integrating them