I have 7 nine week old chicks (6pullets & 1 roo) starting the integration with my 9 25week olds (8 hens & 1 roo). I have had the littles in a fenced in area next to the large coop so they can see each other for for a few days now. Opened a small spot in the fencing so only the babies could come and go, when 2 did venture into the big coop my rooster went after one. My black Australorp also kept going after them, she is seeing impaired and I’m guessing she wasn’t quite sure what they were or maybe because that would put her at the bottom of the pecking order with the big ones? I have no issues with the different breeds of my big ones and have never had anyone pick on another. Do I try again with the babies in a few days? Should I try integrating outside in the run and not in the coop? Most of my flock was outside when I made the opening for the babies, but my big ones always come and find me when I’m around. I also have 3 nine week old bantams (2 are roosters) and 3 five week old bantams that I still have in my sunroom. But figured I would integrate the others first.