My neighbor locks a large pup in a cage that is not big enough to move. I heard him crying night and day and went to see if he was OK, and saw him both times in a cage too small for a dog half his size. What can I do?

All animal abuse must be reported. Animals have rights too and it is cruel and stupid to sit back and watch people abuse their animals and not intervene (in a sensible manner!)

I am going to be realistic and it may not be what you are expecting. However these are questions that need to be asked.

How are you determining that it is too small for him? Can he stand up? Can he turn around? Where is the cage? Inside or outside? Do you know how much time he is in and out of the cage?

What about his other needs? Food and water? Play time and exercise? Potty time? Properly fitting collar? Grooming? Is there physical or verbal abuse?

I commend you for caring about the animal but you are very limited in what you can do unless you have proof that the animal is being abused or his barking is a nuisance to you. Reporting him and/or them could have consequences such as him being removed the house. Do you think he would be better off in a shelter?

One place to start is talking to his owners, have you?

.. particularly since in many shelters if they aren't adopted out in 30 days they are euthanized.