Are blue heelers aggressive?

No, blue heelers are not aggressive. However, they’re very loyal to their family and might be protective around strangers. This means they need to be socialized from puppyhood so they learn not to be too wary around new people.

If you want them to be around other pets, for example, cats or chickens, it’s also important to introduce them while your blue heeler is still a puppy, so it learns to be friendly towards other animals.