I can understand how you feel so torn!!! Of course you want to be nearest to your Niki! How far away does your Dad live? I was thinking, if you're going to be busy all of the day at school (not able to spend much time with Niki) and your Dad lives close enough for you to visit readily, I'd have to vote for leaving her there with your Dad; for a couple of reasons...

You Dad obviously loves Niki a lot, is lavishing her with love and I'm sure, would be very sad to lose her.

Your Mom, well I'm uncertain from your post how attached she is to Niki or dogs in general. But it is sad to think that Niki would be spending day and night outdoors.

And by now, I'm sure Niki has developed a special bond with your Dad too, being spoiled rotten to boot And perhaps, she would feel a bit of confusion over the move.

So, if you're still able to visit reguarly, as hard as it would be, I'd say for now, while you're in college, leave Niki with your Dad.

My heart aches for you...I know how difficult a decision this is. Hope others will chime in!