I have a wonderful lab mix puppy. He is about 4 months old and has really been a joy. We adopted him from a humane society 2 weeks ago. He is a great dog in the house but outside is a whole other story. I walk him at least twice a day and he insists on putting everything in his mouth. It is usually a stick but sometimes it is rocks. He usually drops them at some point but has swallowed a few pebbles. My husband (who doesn't do any of the walking) is complaining that we should muzzle him to prevent it and I do believe it s out of concern. I have explained that he is just learning about his world and will hopefully outgrow it. I feel like I spend more time saying "no" or prying rocks out of his mouth then I do just enjoying being with him. His vet says he is fine and will stop as he gets older. For now do I just let it continue and is it normal?