maebe

I would have to go with bunnies be the most valuable. You can breed them for meat and have something other then just vegetables all the time. They wont make much noise like other animals and there for will not attract near by zombies. Also small enough to easily move a pair for future breeding and/or for a pet. Plus if someone wants to steal your bunnies you hide them in a top hat. Then no one can find them and they are safe.