House Training an Abused Chihuahua?

We rescued a Chihuahua from my sister and brother-in-law, who adopted him from a shelter. He is about three years old. When they first got him, he seemed like a good dog. I went to their house to babysit for a few days and he was also part of the babysitting.

He would growl at my brother-in-law whenever he walked into the room and he would cower behind my legs or whatever else he could fit behind. My fiance and I offered to take him off their hands. We brought him home to our kitten and 2 year old Pit/Lab mix. The Pit mix dog is very friendly and loving. He has gotten rather territorial since the new dog got here, mainly with food, but we are working on it.

The Chihuahua, Ned, is a good dog. We know my brother-in-law abused him. He growls at any man that walks through the door and hides in his kennel or whatever he can get behind. He never lets me know when he needs out. I can take him out six times an hour and he will do nothing until he gets back inside, where he will both pee and poop on the floor.

He is a very skittish dog. You can get up and walk across the room without even acknowledging him yet he will shoot up from wherever he is laying, bolt behind something or make sure that whatever direction your back is, he will be behind you.

He gets along great with our other animals and our 1 year old baby. If a man is around, he growls. If a man tries to pick him up, he snaps at them. My fiance was walking through the living room the other day, Ned freaked out and started growling at him and nipped at his foot as he walked by when my fiance wasn't even paying attention to him. He just did it out of fear for the guy that abused him. Then he ran away and pooped in the other room without a sound or whimper to go out.

Even when he is not feeling scared or threatened because a man is near, he will still not let you know he needs out. I have no idea what to do.

By Sarah E.