6wk olds in with bigguns?

[GlitterKitty]

Alright, I know I am not supposed to do this...but can I try? We cannot come to a solution of how the chicks and bigguns can get in the coop during the day. Neither can be locked inside as gets WAY to hot in there. And no one can free range as my dog will eat them. Once he smells a chicken he digs out of his pen. I built a little pen and was wondering if the pen had a tiny opening only the chicks could get into. Then have another pen like that outside. Were leaving on vacation monday to. And my mom wants the chicks out of the house today.
Also I have alot of bantam hens that have all been broody conistently, what if I introduced them to the chicks, would broody take care of them even though their six weeks old?

Thanks for any suggestions!