ratings for stores?

[lazydays]

I know that stores often employ people part time to avoid paying health benefits, Walmart being the poster child. I would prefer to spend my money at stores that treat their employees well even if it costs me a little more. So Walmart, Target, Fred meyer, Kmart are all pretty similar in what they sell, how can I find out who treats their employees the best? Maybe it is just a game but I'd like to know.