Walmart CEO says the biggest 'hazard' for in-home grocery delivery is dogs

Walmart has started delivering groceries inside customers' homes.

And you might not expect this is the biggest problem Walmart's CEO says the company is running into: Dogs.

"We have this place on the app where customers can tell us whether they have a dog or not," Doug McMillon told CNBC's Becky Quick from the network's Evolve Summit in Los Angeles this week. "And sometimes they misinform us about whether the dog is in the house, or not in the house."

"We've had a few instances where we just stop the delivery, exit the home, call the owner and say, 'We'll need to resolve the dog issue before we put your food in the refrigerator.'"

So running into dogs "big and small" has become a "new hazard of working at Walmart," he said.

Walmart in October started trying an in-home delivery option, which costs $19.95 a month, in Kansas City, Pittsburgh and Vero Beach, Florida. It has said it plans to scale this offering "aggressively."

In order to make deliveries, Walmart employees must have at least a year of service with the company, background checks, motor vehicle record checks and extensive training, according to the retailer.

Walmart shares have climbed about 28% this year. The retailer has a market cap of about $341 billion.

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