Puppy pen A Maltipoo, a Chihuahua and a Labrador Retriever play together in the puppy pen. A Maltipoo, a Chihuahua and a Labrador Retriever play together in the puppy pen. What a wild time the three of them are having! They romp around on the cuddly blanket, compete for the teddy bear and play hide-and-seek. In between, they take a well-deserved nap in the dog basket. Fun fact A small fence keeps the three curious puppies from running away.