Sorry about that last post. I was a little out of it yesterday.
In any case, I still don't think that Hogback necessarily wants the strawhats for their bounties. It's a fairly safe bet that Perona learned their bounties while he was casing the ship. The mugiwara are proud of their bounties and would probably hang them up on a wall somewhere.
As KoF pointed out, bounty hunters are fully capable of referring to their target's as prey. However they generally don't go dancing around the forest going
Things: (New prey, new prey, kekekeke)
That's just too maniacally jolly for someone making ends meet by hunting vicious criminals.
There are a couple of other circumstantial difficulties with Hogback turning in pirates for bounties:
1. Who would turn them into the government? A zombie would be killed on sight by the marines and Hogback is too well known in the medical field to be regularly visiting marine bases in the West Blue without the scientific community learning his whereabouts.
2. All of the zombies except the weird animal/trees and cindry look like pirates. Were these willing subjects? Ancient corpses? Check out 445 and you have to notice that the zombies in the graveyard have distinctly pirate-like styles of hair and facial hair. You would imagine that if Hogback simply raided a village's graveyard there would be some more female/child zombies than just cindry and the mona lisa.
3. For what purpose would Hogback want to turn in bounties? He's the most preeminent surgeon in the world according to chopper. He could charge his patients whatever he wanted as he can save their lives when no one else can. A doctor at that level is a walking mint, so why risk his life and waste time traveling the seas on a floating island trapping pirates for mostly piddling bounties?
4. They never do explicitly mention how they are going to get rich off of this or that they are bounty hunters.
One other plausible alternative would be that Hogback goes around capturing pirates to harvest their bodies to give their strength to his minions or to turn them fully into his zombie slaves. If this were the case, Hogback would still be excited over their bounties because of what the addition of their strength would mean for his future endeavors. If he is creating enough strength to potentially threaten a crew as highly rated as the mugiwara, then he is hoping to use that strength for another purpose as well.
The evidence concerning this issue is circumstantial no matter what your view on it. Hogback has not yet mentioned what his actual plans are. Personally, I don't think that the idea of zombie pirate hunters fits in very well with what we know about One Piece lore or the nature of Hogback's experiments.