What age do I introduce new chicks?

[8 divine chicks]

I have 8, 22 week old chickens. I also have 5, 7 week old chicks. The chicks have been in a screen run next to the older chickens for about 1 month so they can see and get better aquinted and they sleep in the coop in an enclosed box. When can I safely mix them together?

 

[Opa]

when they are approximately the same size as the birds you are going to put them with.

 

[Katy]

I try and wait until the younger group is about the same size as the older ones. That way they have a chance of defending themselves while the pecking order is being sorted out.