Is that the type of shredder they used though? It seems too slow especially when considering live squirrels. I imagine it would be more like the one used to kill male hatchlings in the poultry industry[1]. Quicker and bit more humane.
[1] -https://www.youtube.com/watch?v=udSiluTAOaQ (warning : potentially disturbing footage)
Article noted industrial, which means they were probably using a high-torque, low-speed machine (aimed at pallet shredding).