Walker by Shoo Rayner
All Walker wants is a dog, but his mother is allergic. So he decides to set up his own business walking everyone else's dogs. This works better than he could have imagined when he finds he can talk to dogs and understand what they say to him! The dogs tell him of a terrible puppy farm hidden in the woods by Arlington Wherewithall, the richest, most famous man in the area. Nobody will listen to him, so it is down to Walker and the dogs to stop the farm and save the puppies.