Photos won't sync to iPad; storage space is shown to be used and synced successful on iTunes, but nothing in Photos.

I am syncing about 28,000 photos from my company's server to the iPad. iTunes shows the correct amount of storage space to be used, I click "sync" and it does its thing, until Step 6. It will be stuck on "Syncing Data," and suddenly the "Photos" data seems to be part of "Other." On the iPad, no photos are shown on the camera roll, but the storage is full. Currently it has been syncing for about 20 hours without completing.

Thanks for your help if you have any tips!!