I got a chihuahua puppy 2 months ago and I know what it's like, we're still dealing with it. She would literally scream without end whenever she is left alone. We tried ignoring it and now the screaming has fizzled into whining but it's not as constant and to keep her quite at night she's crated in my mom's room, a couple of times she even slept alone quietly through the night. So ignoring it does help but it takes so much time and persistence. When you do go to let your puppy out be sure that it's when your puppy is quite and not when he's whining otherwise he will think that the whining got your attention.

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