Multiple animals in a building

[The_Esquilax]

I’m frustrated because I can’t seem to put 2 (size 1) animals in a size 2 or 3 building. What feature am I missing?

[Tisaac]

I’m frustrated because I can’t seem to put 2 (size 1) animals in a size 2 or 3 building. What feature am I missing?

The fact that it's forbidden ?

[Remkar]

I’m frustrated because I can’t seem to put 2 (size 1) animals in a size 2 or 3 building. What feature am I missing?

Animals can only be placed in empty enclosures (with the exception of the flocking ability and the special buildings like reptile house/aviary).

It is also useful to note for multiple other rules/situations, that once an enclosure is flipped from empty to filled, the game has no memory of what animal is in there.
For example, if you place a size 3 animal in a size 4 enclosure, but then later are releasing an animal (say for a conservation project), and you choose a size 3 animal, IF you have a filled size 3 enclosure at that point, you MUST free up that enclosure, even if the animal you're freeing was placed into a size 4 enclosure originally.

[vikingerik]

Yeah, the game doesn't work that way. It's always only one animal per enclosure*, even if the enclosure is bigger, the extra space is just wasted, you can't put another animal in.

(*except flocking animals, petting zoo, reptile house, large bird aviary.)

[Jellby]

What makes you think you could put a fox and a rabbit together in a very large enclosure?

[Nomark21]

Maybe if there was a stream in the middle and a rowing boat?

Oh and rabbit food