My chihuahua has free reign of my apartment. Better yet....HIS apartment, lol. However, when we come to visit my parents at their house and there's no one home, we do put him in his "big cage" with my sister's pitbull. I know....before anyone gets any ideas and starts yelling at me, my chihuahua and the pitbull have been raised together since they were puppies. Bubbles would NEVER hurt my Luca. Bubbles will actually cry if I try to take Luca upstairs and leave her alone. Luca is her baby, and does treat him that way.
Now....with Adrianna....I do plan keeping her in an ex-pen when I'm not home at my apartment. Also, when I do come to visit my parents, I'll definitely bring the pen with me as well.
I'm attaching a picture of my chihuahua and my sister's pitbull all cuddled up together!