Just wanted to share a little update and progress. But first a little background.
About two weeks ago I moved the two pullets into an adjacent run with the three older hens where they can see and hear each other through some chicken wire. During those first few days a couple of times (intentionally and unintentionally) the pullets got out into the main run and it was hostile. They were quickly chased and pecked pretty darn good with some screaming involved. Didn't think my sweet buff orpington could be that mean, but boy was she ever. Just about everyday since they moved into that adjacent run I've put their favorite cracked corn down along the gate that separates them so they are practically face to face all eating together.
Starting last week, about 3 or 4 nights I had been letting the little girls out to free range with the bigger hens. I sprinkled in some cracked corn in attempt to get them to feed together. There was some chasing and pecking but not too terrible. The two pullets are scared to death of the bigger hens, as soon as one of them turns towards them, they are outta there, sometimes screaming for no reason, it's actually pretty funny. They are way faster than the buff orpington (Elsa). She seems to be the only one who really cares. My easter egger could care less, hasn't once tried to peck or chase them. My plymouth rock will chase a little but never closes in to peck, it's like the chase was enough for her, no need to peck, she is a sweetie.
This past long weekend despite the rain I spent a lot of time with them, letting them out to free range and interact with each other. And what an amazing difference I see. The chasing has pretty much all but stopped. Even when there is some chasing it not as nearly as aggressive as it was initially. I even had them all in the coop together (with the gate open) several times and it was completely different. The older hens went about their business for most part, if they chased it was a few steps just kinda to make sure the younger pullets were knowing their place and getting out of their way. What a difference, this being my first time owning chickens and doing an integration like this I was really nervous about what I saw with their first few interactions but I am feeling so much better about all this and I can see them all getting along at some point.
I plan on keeping them separated for a bit longer just because I can and will continue to do what I am doing so they get a little bigger.
Really some great advice on this forum and without a doubt keeping them separated but being able to see each other I truly believe has made a HUGE difference. It really seemed to have diffused the aggression.