When can I let the young birds in with older birds

[Chicken of the Sea]

I have Autralorps that are 8 weeks old and Rhode Island Reds that are 4 weeks old. Obviuosly there is a huge difference in the size of the birds. At what age will it be safe to mix the flock?

 

[Roy]

I just put my 8 week olds in with my hens the other day, they all to be very content. All are doing well...

 

[Mahonri]

I'd wait four more weeks.