I have too much stuff in and around my house, I didn't need, nor want to buy a deer hauler too, but I am getting old and weak and feeble. I came up with an idea that works surprisingly well, using stuff I had on hand.
1) old, cheaper two wheeled cart. This one has wider pneumatic rubber tires. Spreads the load well. It also has runners in the back for stairs.
2) piece of plywood. I used 1/2" cause that is what I had laying around. I cut it to fit and glues and screwed two support boards along the bottom. If you look, these fit under a cross member and keep it in place. I also drilled periphery holes to allow me to tie a deer in place.
3) I turn the handle of the cart around for hauling deer, cause I am tall and don't want to bend. I have used this cart in sand and mud, and because of the runners, I can go right over fallen trees. Turned out slick. Then, I stash the board till next season and use it as a two wheel cart again.
Tie the deer head up near your handle, the rest is supported nicely along the rack.
ChuckC