Need some help introducing chicks

This past weekend we got 2 new chicks. I would say maybe 12 weeks old and a silkie that's maybe around 20 or a little more. We have 3 Is a browns and 2 other silkies and a male and female Rouen duck. I tried putting the new girls in at night like I heard to do but it's not working the Isa's are still picking on the chicks and chasing them. The one RIR that we just got hides under my feet when I go out there. The EE runs away and hides in the corner and the silkies runs away squawking. Any other tricks you guys have up your sleeves? I feel bad for them.