How is a little girl zombie picking up a toy evidence of a hive mind????
Just no. There has been no evidence that brings a hive mind even close to being canon.
Zombies do not share a hive mind, or work for a common goal, but it seems like they have some ability to sense the location of humans, long before they are in range of odor, movement, etc. If that is the case, it adds another level of creepy to the situation, as it implies they will find humans no matter how far they run.