I wonder this too. Avalon seems pretty firm in the belief they are two separate breeds, yet says her dogs and the Koolies we know best on Chaz share common dogs in their pedigrees. Wouldn't that make the Avalon dogs Coolie x Koolie mixed breeds? It's true, although there are some very convincing mixed breed lookalikes out there! Especially with the SFs. Friends of mine had a dog they got from the pound in the 90s who really, looked very much like a SF black PyrShep. Speciafically looked like the dogs from the litter agility PyrSheps Luka and Boo came from. If someone had him at a PyrShep get together and didn't say he wasn't one...I'm not sure anyone would have questioned it. I have seen some solid merle mini-Aussies who were pretty good SF look a likes too (and actually, have heard people at shows thinking the natural bobtail SF merle was maybe a working bred Aussie). Really though...Aussie or PyrShep?