Bantam bully

[Poodlemum]

Is it just the one that's being aggressive

There’s two, but one is much worse. Then they fight with each other as well

 

[artsyrobin]

Get some boredom busters in there, and litter, so they have stuff to kick around. Mirrors, bottles with holes punched in them, put feed in it. A small perch to sit on.