We have been using a deer sled to haul out animals at our deer camp. We have ATVs and a wheeled cart but the sled works the best. No lifting the animal, just roll on and tie down and the bikes stay clean with no blood to wash off. It will go over logs, down ravines, through creeks without a problem. I’ve pulled enough bucks up onto a ATV and it’s a PITA and then you have to truss them up like a turkey and make sure the rack doesn’t hang into the wheels.
I recently upgraded the drag and took some pictures in the below slideshow of the old and the new. It is just a car hood, a drawbar made from some perforated sign post and a hitch connector. We use an old 1 7/9" ball connector to hitch to the bike. The old sled worked great but I occasionally caught a tree or shrub as it was pretty wide. One of my friends liked mine and made one that was a bit narrower. He had the side bent up to make it thinner. This is how I wanted to upgrade ours. I got an old hood from a friend who runs an auto collision shop and took it to my highway department where some other friends work and they bent the sides up on their big metal brake. I took the old hood off the drawbar and drilled holes. 3/8" bolts work well. I used some Eyebolts for some of the attachments and also for some tie down points around the hood. I added a plywood shelf in front of the hood attached under the drawbar with a few tie downs. This keeps the head from flopping in front of the sled.
There are two downside to the device. It makes noise going down a dirt/gravel road and in mud, the animal can get dirty from the bike wheels. It’s best to drive slow but I had the going pretty fast. Wrap a tarp around the deer if you are going the mud route.
http://s264.photobucket.com/albums/ii179/Chuckermaroo/?action=view¤t=70e269b5.pbw&t=1253501434