So sorry!
We had the same thing happen to us last week!
When we got our first Brahmas from TSC back in April a few of them ended up being Sebrights.They were labeled dark brahmas and they were all the same size
Fast forward to last week ...... we ended up with 3 Seabright roosters and two pullets. The one roo killed one roo and injured the other. We were able to save him . The really mean roo is gone also. hubby took care of that! Now the three Seabright that are left are starting to pick on my beautiful10 week old laced brahmas. This started yesterday.All of my birds free range but I keep the younger ones in a big fenced in area. now the sea brights are getting in the pen picking on my brahmas! They are out of here!