Walmart is laying off the robots it had deployed in about 500 stores to keep tabs on what's on and not on the shelves. The retailer said it has ended its relationship with startup Bossa Nova Robotics, which builds roving robots equipped with cameras for identifying out-of-stock and misplaced products. Walmart said in a statement it has "worked with Bossa Nova for five years and together we learned a lot about how technology can assist associates, make jobs easier and provide a better customer experience." It said it is still testing other new technologies for tracking inventory and moving goods. "This was one idea we tried in roughly 500 stores just as we are trying other ideas in additional stores," Walmart said in a statement. The Wall Street Journal was first to report the ending partnership Monday, citing unnamed people familiar with the situation who said the retailer found human workers could get similar results.