Aggressive pullet. What should I do?

[TheOddOneOut]

So I got two new 6 week pullets on April 25th. I introduced them on May 8th to my existing group of four 6 week old chicks, two of which are suspected roosters. The original four are:
1 Blue-Laced-Red Wyandotte x White Ameraucana named Vanilla, who was alpha of the original 4. She is very curious and gets picked on by Mel the most, probably because she was the alpha.

1 Speckled Sussex, Nutmeg, who is the smallest chick but seemingly the smartest and fastest. She is only half the size of new pullet Melody. I am pretty sure she is a SS, but her pattern is not clear at all, and she has feather stubs on the tops of her legs. Of course, they are all hatchery quality.

And 2 Dominiques, Salt and Pepper, who both look to be boys. Salt is bolder than Pepper, who is quite cuddly.

The two new pullets, about a week and a half older:
Melody, a Buff Orp with a beautiful sweet voice. She is the one that has been aggressive towards the younger chicks.

And June Bug, a chipmunk-patterned EE who is as sweet as they come with the younger chicks. Melody is super protective of her though.

So I have read that Buff Orpingtons are super docile and sweet. Not the case with Mel. I mean, she is sweet with people, as long as we don't pick up June Bug, who Mel is super possessive of. But she is aggressive to the younger chicks. She pulls feathers if they get in her personal space. The pecking order has already been established. She is very much on top. Now she's just being mean. The younger chicks run from her even when she's not being aggressive. They hide from her in the roost sometimes, which is a problem on hot days, because it is very warm in there. They have plenty of space in the coop to run, but I don't like her behavior. What should I do?

 

[BantyChooks]

It's only been four days—it takes a significant time longer for different groups to be fully integrated with each other. It is my opinion that any attempts to separate them would only prolong the issue, so in circumstances where I have similar issues, I give the bullied birds plenty of places to hide, such as under shelters, behind visual blockers, or up above the bully's reach. Be careful to avoid placing shelters in a manner that would allow birds to corner each other.
Additionally, I would recommend placing more feed and water stations at enough of a distance that one bird cannot police both of them.

 

[TheOddOneOut]

It's only been four days—it takes a significant time longer for different groups to be fully integrated with each other. It is my opinion that any attempts to separate them would only prolong the issue, so in circumstances where I have similar issues, I give the bullied birds plenty of places to hide, such as under shelters, behind visual blockers, or up above the bully's reach. Be careful to avoid placing shelters in a manner that would allow birds to corner each other.
Additionally, I would recommend placing more feed and water stations at enough of a distance that one bird cannot police both of them.

I did put their chick water station in there, but they often knock it over. And it doesn't hold much water and gets emptied fast. But they have water she isnt't guarding, so it works. Thanks for the advice about hiding spots!