I would like a small to medium size dog to bark at cats and whoever else might be around the house. I also have 5 kids age 1-10 that are real handfulls. The dog would be able to go outside or come in whenever it wants, I have a large backyard and large covered concrete patio. In the paper right now I see some free Red Heeler/Border Collie mix puppies, also some Chihuahua/Schnauzer puppies. I saw some yellow labs too, but they may be a bit too big. Any helpful ideas? I really prefer a dog that is pretty calm for the most part when it's older.