We're not supposed to handle stuff like that as it can be considered a bio-hazard. However; some Authorized Shipping places (like grocery stores, for example) will take pre-sealed packages and not inspect them for proper packaging or prohibited materials. They're supposed to, but what can you expect from a place that ships packages, sells lottery tickets, and refunds your 7 cents you overpaid on Cheetos all at the same counter?
As for dead mammals, I've seen coolers shipped (during hunting season, typically) full of meat packed in ice. Ice only lasts so long, if you know what I mean. If it ain't sealed properly, odors get out and a searching we must go. Dry ice may make it last longer, but in Phoenix, not much will keep raw meat cool when it's sitting in a giant metal box.
The weirdest (and grossest) thing would probably have to be a quarted Elk carcass that was discovered in a plastic bag, in a cardboard box. No ice, no cooler, nothing. I won't be too graphic, but let's just say that although the Elk was deceased, not everything in the bag was...
Runners-up for weird things:
- Case of lady bugs that had a broken latch. Ever seen a bazillion lady bugs loose in a warehouse building?
- Box of worms (not dead)
- Loaded shotgun (that went off while in the box)
- Assembled desk chair (no box, just a label tied around the arm)