If you are able to get some that are about the same age as the ones you have that would make integration easiest. You will need to keep them separated from each other but in view of each other for the first few weeks. There are multiple threads on BYC that explain how to integrate new chickens...
You could also show the pictures that you posted here. It’s very evident in the photos as both of them have very significant saddle feathers. If you don’t know what these are, these are the feathers just before the tail across the lower back. They are pointy.😊