I'm a taxidermist-in-training and I've had to freeze several specimens (not chins mind you!) for later use... This is the method I use, however terrible it may sound:
I suggest wrapping in several layers of paper towels, it'll absorb any fluid leakage. Rip a basic small garbage bag at the seams and wrap it around the body, this'll prevent freezer burn. Then put in a zip-lock baggie making sure to remove as much air as you can.
If it was for any length of period longer than a day, I would suggest freezing. I've frozen several squirrels this way and they've shown no obvious organ/tissue damage, but on a molecular level, I'm not entirely sure it destroyed any bacteria --- good or bad.
Wrapping the animal in either newspaper or paper towels is incredibly important as it protects the body from external factors/damage.
Good luck finding some some answers and I'm very sorry for your losses.
