I am thinking about adopting a blue heeler dog, and im wondering if it would be a good dog.?

Blue heelers are excellent dogs! They should be outside most of the day with LOTS of room to run, when you say BIG yard are we talking an acre? half an acre? what? we had them growing up and they need more then jsut a large backyard, if thats all you can offer make sure you walk the dog daily and do activities with them that will allow them to blow off lots of steam. They like to be close to their families as well so bringing them in at night is best. Or when its super hot or cold! They are hurding dogs so keep that in mind. They will get along ok with your cats, and they love kids.