Volunteers = Liability which costs money.

I do agree that the employees are not at fault, not necessarily that they are there because they like the animals, but like anyone else, they need a paycheck. The stores don't put forth the money, time and effort to properly train anyone to be knowledgeable about the animals, much less specific species. Just not many people working minimum wage(or close to it) jobs that are going to go out of their way to learn more about their field of work on their own time.