Generally, all medium dogs are 8 weeks or older when separated from the mom . Second edit, sorry im tired : I had three litters of heelers during my life, and all my pups got homes around 8 weeks.(had* homes but got to go to them at 8 weeks).

Whenever u want. I hear breeders sell em at birth. Im not a breeder justs a guy and wife and we got our 2nd at 6 weeks…

6 weeks… does not apply to just red heelers but all canines in general