I realize it's been over a year, and I haven't been very active on BYC lately - actually I just now feel settled with the move, fixing up the house and adjusting to a new baby - but I wanted to update this thread.
We now have a new dog - a mixed Chihuahua (yes, quite a change from having all those large dogs!). I was skeptical at first because I used to think they were bred purely to be companion dogs, but he's actually very territorial and excellent in warding off foxes, stray cats, dogs and even our neighbour's goats! He's tiny, so no danger of him knocking my children down to the ground, and my 6-year-old walks him quite comfortably. Today I saw with my own eyes how he chased away a dog 20 times his size (I'm not kidding!). Also he doesn't see chickens as prey since he's about the size of a rooster himself. So, just letting everybody know we DO learn our lessons.