How do the animals die, and do they leave anything behind? So far I have figured out that piggies will die if not fed they will die/ leave x10 meat. Butterflies on the other hand have a life span, and eventually they just die... or if overcrowded they will leave. And I have heard they leave butterfly milk/butterfly eggs (only if they die though). For chickens, they will die if not squeezed or over-squeezed. Also if they get overcrowded they will leave.
So my basic questions are: Do pigs leave if overcrowded? Can butterflies die any other way? Same with chickens?
And if I missed anything or over-exaggerated some things or got anything incorrect, please let me know. And please tell me anything you know related to this :)