No animals at all?

I keep waking up to pm's from people saying there are no animals at all on my server, what could possibly be making this happen? I'm not using anything that modifies animal spawns or anything. Anybody else getting this?

 

Are you using Cornucopia? Depending on the config it can force extinction on animals... if not, it can definitely remedy your issue. http://oxidemod.org/plugins/cornucopia.1264/

 

Your plugin seems to have fixed my issue