Played a game the other night. The way the zone and path was situated we ended up splitting a large number of zombies per turn.
By large I mean at one time we split a group of 10 walkers, which turned into 20 walkers.
Have you guys ever played a game with a large number of zombies magically appearing from splits?
Dude! You just add zombies to make it an even number!! So, if you have 21 zombies, you have to add one so that 11 can go in each direction. If you have 10 walkers, then 5 go in each direction.
It DOES get frustrating with low numbers, as splitting a group of 1 zombie, you round up so that one goes in each direction. That's about the only time you can literally double.