Bears eat anything. Garbage, rotten road kill, anything. Because of this there mouth, and whole body lives with large amounts of bacteria. The clock starts ticking as soon as its heart stops. The bacteria and rapid decomposition makes its own heat. The hide needs to be removed and the meat on ice fast. Lots of ice. You can't have too much. You can have ice on the bottom, two quarters and ice on top and still loose meat in the middle. Butchered my own one time and cut off the green meat that smelled a little off and kept the rest. Sounds gross but it is possible to keep the good half. A butcher will not want to take the time and I wouldn't trust anyone else's nose to do it for me.
Same goes for the hide. Lots of ice and fast. I shot a 20 inch bear and was going to get him mounted for sure. I gave all the space in the ice chests to the meat, and had the hide with scull attached in a wad sitting on a bag of ice. The heat from the decomposition in the head was faster than the ice could cool. When I got to the taxidermist the tongue and gums were greenish and the bear lost patches of hair when it was tanned. The paws stunk too. The taxidermist had to transplant hair to cover the patches. He saved it but it took a lot more work.
Same goes for pigs. I shot one that ran off and died in the sun at 7:00 am. We found it at 10:00 but it was already bloating and meat was bad on the sunny side up. Black pig in the sun is no good.
