Don't take them out of their cages, they'll just go rampaging around. They need to be tamed before they can be butchered.
Don't you mean "They need to be trained before they can be butchered."?
You can't tame an wild adult (edit) unless your civ has a "Domesticated" familiarity(/edit), and you can only successfully tame their offspring when very young.
Wild adults can only be safely pastured when trained to some degree, and only butchered when pastured but they don't need to be pastured to be butchered.
Only moments ago, I successfully butchered a caged "Stray Giant Flying Squirrel (*Trained*)".
As for semi-wild ones, I've no idea because I've never tried or seen any reason to try. You can also safely pasture a Semi-wild adults.
I hope this prevents any confusion.
(note: This now looks just like my first, and last, feasibility report submission did.) 
Had a question on this.
Caged a Black bear, and the dwarf civ had no knowledge of them.
But slowing trainning him, they were getting the "Your civ is more knowledgeable on the taming of [Black bears]
Can you get it to a point where you can tame wild animals fully?
[Edit for grammar]