Had a Blue Heeler x Aussie cross male, looked like a Heeler. He was pretty massive and broad chested for most Heelers Best dog I ever owned But after he was over 10 years old started getting ornery, wouldd no longer always obey or come, bit two strangers coming in drive-way and I could not "call him off", as I always could in the past. I have Grandchildren here all the time. Had to put him down.
Now have an eight month old Heeler/Aussie cross (cow dog families). Looks more like an Aussie, slighter framed, yet taller, long heired, colored like Aussie. Sire was an Aussie, dam was a Heeler. Pretty good so far, but too young to know. Seems friendlier an more socialable than Heeler, More spastic or air headed than the "old dog". Chases birds, bees, butterflies and bites my wifes flowers off the stem in her rock garden (this is NOT good). Hopefully, this is still just "puppy stage" and he will grow out of it. Also, I did take him to the vet and had him castrated at approx. five months of age. Seems very smart and I can tell he has some of the "instincts.