My first clutch of chicks I waited till 4 weeks to integrate and it was difficult and a lot of bullying. Then I found out about brooding in the coop. Now If I don’t have a broody to raise chicks, I section off an area for the chicks at a week old I move them out with their heating pad brooder plate.
View attachment 1912641 After watching the older flock for a few days they start venturing between the gate but can get back to their area if bullying, to eat or nap under the heat. My older silkies can’t get in there. Tiny chicks are not a threat like larger chicks so by week 3 they are spending all day with the flock integrated no issues.
If the rest flock is accepting but Oogy is being the bully. I would put her in the cage for a few days.