Chickenduck, I feel for ya. When you put the time and energy into teaching your pets to behave a certain way it just drives you nuts to have it disrupted. I have a roommate who has managed to ruin my dogs. Before she arrived, they were well mannered 'fur kids' who were welcomed visiting friends or family. Now, I have to lock them up if I know someone is coming over. Or if they arrive un-expected I have to either go out and escort the person across the yard, or drag the dogs inside and put them in a bedroom. They beg, fight over food, jump on people, race out any open door - and when possible in open doors too. They can no longer be allowed out of the fenced in yard without a leash because recall no longer exists. It's maddening to say the least.
Thankfully, your sister in law was only visiting (right?) so you can just make it clear that her dog is no longer welcome in your yard.
Did you say that the dog nearly killed one of your chickens??? How is the bird now? Did she recover?
Also, I'm sure War Chicken was kidding. I LIVE by spell check because I can't spell worth a hoot. What gets me is when you spell it right so spell check misses it, but it's the wrong word.